Control method for tintable windows

ABSTRACT

A method of controlling tint of a tintable window to account for occupant comfort in a room of a building. The tintable window is between the interior and exterior of the building. The method predicts a tint level for the tintable window at a future time based on a penetration depth of direct sunlight through the tintable window into the room at the future time and space type in the room. The method also provides instructions over a network to transition tint of the tintable window to the tint level.

FIELD

The embodiments disclosed herein relate generally to window controllersand related predictive control logic for implementing methods ofcontrolling tint and other functions of tintable windows (e.g.,electrochromic windows).

BACKGROUND

Electrochromism is a phenomenon in which a material exhibits areversible electrochemically-mediated change in an optical property whenplaced in a different electronic state, typically by being subjected toa voltage change. The optical property is typically one or more ofcolor, transmittance, absorbance, and reflectance. One well knownelectrochromic material is tungsten oxide (WO₃). Tungsten oxide is acathodic electrochromic material in which a coloration transition,transparent to blue, occurs by electrochemical reduction.

Electrochromic materials may be incorporated into, for example, windowsfor home, commercial and other uses. The color, transmittance,absorbance, and/or reflectance of such windows may be changed byinducing a change in the electrochromic material, that is,electrochromic windows are windows that can be darkened or lightenedelectronically. A small voltage applied to an electrochromic device ofthe window will cause them to darken; reversing the voltage causes themto lighten. This capability allows control of the amount of light thatpasses through the windows, and presents an opportunity forelectrochromic windows to be used as energy-saving devices.

While electrochromism was discovered in the 1960s, electrochromicdevices, and particularly electrochromic windows, still unfortunatelysuffer various problems and have not begun to realize their fullcommercial potential despite many recent advances in electrochromictechnology, apparatus and related methods of making and/or usingelectrochromic devices.

SUMMARY

Systems, methods, and apparatus for controlling transitions ofelectrochromic windows and other tintable windows to different tintlevels are provided. Generally, embodiments include predictive controllogic for implementing methods of controlling tint levels ofelectrochromic windows or other tintable windows. Typically, the controllogic can be used in a building having one or more electrochromicwindows located between the interior and exterior of the building. Thewindows may have different configurations. For example, some may bevertical windows in offices or lobbies and others may be skylights inhallways. More particularly, disclosed embodiments include predictivecontrol logic that provides a method of predicting and changing the tintlevel of one or more tintable windows to directly account for occupantcomfort. The method can determined the tint level for a future time, forexample, to allow for the predicted transition time of the tintablewindows.

The comfort has to do with reducing direct glare and/or total radiantenergy directed onto an occupant or the occupant's area of activity. Insome cases, the comfort also has to do with allowing sufficient naturallighting into the area. The control logic may also make use ofconsiderations for energy conservation. In a particular implementation,control logic may include one or more modules with at least one of themodules being associated with occupant comfort considerations. One ormore of the modules may be concerned with energy consumption as well.

In one aspect, one or more modules of the control logic may determine atint level that is determined based on occupant comfort from directsunlight or glare on the occupant or their activity area such as theirdesk. These modules may determine how far into the room the sunlightpenetrates at a particular instant in time. The modules may thendetermine an appropriate tint level that will transmit the level oflight that will be comfortable to the occupant.

In another aspect, one or more modules of the control logic may modifythe tint level determined based on occupant comfort to also take intoaccount energy considerations from predicted irradiance under clear skyconditions. In this aspect, the tint level may be darkened to make surethat it performs at least as well as a reference window required in thebuilding as specified by the local municipality codes or standards. Themodified tint level will provide at least as much energy savings incooling as the reference window. In some cases, the tint level may belightened instead to provide energy savings in heating.

In yet another aspect, one or more modules of the control logic maymodify the tint level determined based on occupant comfort and predictedclear sky irradiance to account for actual irradiance. The actualirradiance may be different than the predicted irradiance due toobstructions and reflection of light. A photosensor or other sensor thatcan measure radiation levels can be used to determine the actualirradiance. These one or more modules determine the lightest tint levelthat transmits as much or less light into the room than the tint leveldetermined based on occupant comfort and predicted clear sky irradiance.

One embodiment is a method of controlling tint of a tintable window toaccount for occupant comfort in a room of a building. The tintablewindow is located between the interior and exterior of the building. Themethod predicts an appropriate tint level for the tintable window at afuture time based on a penetration depth of direct sunlight through thetintable window into the room at the future time and space type in theroom. The method provides instructions over a network to transition tintof the tintable window to the tint level.

Another embodiment is a controller for controlling tint of a tintablewindow to account for occupant comfort in a room of a building. Thetintable window is located between the interior and exterior of thebuilding. The controller comprises a processor configured to determine atint level for the tintable window based on a penetration depth ofdirect sunlight through the tintable window into a room and space typein the room. The controller also comprises a power width modulator incommunication with the processor and with the tintable window over anetwork. The power width modulator is configured to receive the tintlevel from the processor and send a signal with tint instructions overthe network to transition the tint of the tintable window to thedetermined tint level.

Another embodiment is a master controller for controlling tint of atintable window to account for occupant comfort in a building. Thetintable window is located between the interior and exterior of thebuilding. The master controller comprises a computer readable medium anda processor in communication with the computer readable medium and incommunication with a local window controller for the tintable window.The computer readable medium has a configuration file with a space typeassociated with the tintable window. The processor is configured toreceive the space type from the computer readable medium, determine atint level for the tintable window based on a penetration depth ofdirect sunlight through the tintable window into a room and the spacetype, and send tint instructions over a network to the local windowcontroller to transition tint of the tintable window to the determinedtint level.

Another embodiment is a method of controlling tint of one or moretintable windows in a zone of a building to account for occupantcomfort. The method calculates a future time based on a current time andbased on a predicted transition time of a representative window of thezone. The method also predicts a solar position at the future time anddetermines a program designated by a user in schedule. The programincludes logic for determining a tint level based on one or moreindependent variables. The method also employs the determined program todetermining the tint level based on the predicted solar position at thefuture time and occupant comfort. The method also communicatesinstructions to the one or more tintable windows to transition tint tothe determined tint level.

Another embodiment is a window controller for controlling tint of one ormore tintable windows in a zone of a building to account for occupantcomfort. The window controller comprises a computer readable mediumhaving predictive control logic, and site data and zone/group dataassociated with the zone. The window controller further comprises aprocessor in communication with the computer readable medium and incommunication with the tintable window. The processor is configured tocalculate a future time based on a current time and a predictedtransition time of a representative window of the zone. The processor isalso configured to predict a solar position at the future time anddetermine a program designated by a user in a schedule. The programincludes logic for determining a tint level based on one or moreindependent variables. The processor is also configured to employ thedetermined program to determine a tint level using the predicted solarposition at the future time and based on occupant comfort. The processoris also configured to communicate instructions to the one or moretintable windows in the zone to transition tint to the determined tintlevel.

These and other features and embodiments will be described in moredetail below with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C show schematic diagrams of electrochromic devices formed onglass substrates, i.e., electrochromic lites.

FIGS. 2A and 2B show cross-sectional schematic diagrams of theelectrochromic lites as described in relation to FIGS. 1A-1C integratedinto an IGU.

FIG. 3A depicts a schematic cross-section of an electrochromic device.

FIG. 3B depicts a schematic cross-section of an electrochromic device ina bleached state (or transitioning to a bleached state).

FIG. 3C depicts a schematic cross-section of the electrochromic deviceshown in FIG. 3B, but in a colored state (or transitioning to a coloredstate).

FIG. 4 depicts a simplified block diagram of components of a windowcontroller.

FIG. 5 depicts a schematic diagram of a room including a tintable windowand at least one sensor, according to disclosed embodiments.

FIGS. 6A-6C include diagrams depicting some information collected byeach of three Modules A, B, and C of an exemplary control logic,according to disclosed embodiments.

FIG. 7 is a flowchart showing some steps of predictive control logic fora method of controlling one or more electrochromic windows in abuilding, according to disclosed embodiments.

FIG. 8 is a flowchart showing a particular implementation of a portionof the control logic shown in FIG. 7.

FIG. 9 is a flowchart showing details of Module A according to disclosedembodiments.

FIG. 10 is an example of an occupancy lookup table according todisclosed embodiments.

FIG. 11A depicts a schematic diagram of a room including anelectrochromic window with a space type based on the Desk 1 located nearthe window, according to disclosed embodiments.

FIG. 11B depicts a schematic diagram of a room including anelectrochromic window with a space type based on the Desk 2 locatedfurther away from the window than in FIG. 11A, according to disclosedembodiments.

FIG. 12 is a flowchart showing details of Module B according todisclosed embodiments.

FIG. 13 is a flowchart showing details of Module C according todisclosed embodiments.

FIG. 14 is a diagram showing another implementation of a portion of thecontrol logic shown in FIG. 7.

FIG. 15 depicts a schematic diagram of an embodiment of a buildingmanagement system.

FIG. 16 depicts a block diagram of an embodiment of a building network.

FIG. 17 is a block diagram of components of a system for controllingfunctions of one or more tintable windows of a building.

FIG. 18 is a block diagram depicting predictive control logic for amethod of controlling the transitioning of tint levels of one or moretintable windows (e.g., electrochromic windows) in a building.

FIG. 19 is screenshot of a user interface used to enter scheduleinformation to generate a schedule employed by a window controller,according to embodiments.

FIG. 20 is an example of an occupancy lookup table and a schematicdiagram of a room with a desk and window showing the relationshipbetween acceptance angle, sun angle, and penetration depth, according toembodiments.

FIGS. 21A, 21B, and 21C are schematic drawings of the plan view of aportion of building having three different space types, according to anembodiment.

FIG. 22 is a block diagram of subsystems that may be present in windowcontrollers used to control the tint level or more tintable windows,according to embodiments.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the presented embodiments.The disclosed embodiments may be practiced without some or all of thesespecific details. In other instances, well-known process operations havenot been described in detail to not unnecessarily obscure the disclosedembodiments. While the disclosed embodiments will be described inconjunction with the specific embodiments, it will be understood that itis not intended to limit the disclosed embodiments.

I. Overview of Electrochromic Devices

It should be understood that while disclosed embodiments focus onelectrochromic windows (also referred to as smart windows), the conceptsdisclosed herein may apply to other types of tintable windows. Forexample, a tintable window incorporating a liquid crystal device or asuspended particle device, instead of an electrochromic device could beincorporated in any of the disclosed embodiments.

In order to orient the reader to the embodiments of systems, windowcontrollers, and methods disclosed herein, a brief discussion ofelectrochromic devices is provided. This initial discussion ofelectrochromic devices is provided for context only, and thesubsequently described embodiments of systems, window controllers, andmethods are not limited to the specific features and fabricationprocesses of this initial discussion.

A particular example of an electrochromic lite is described withreference to FIGS. 1A-1C, in order to illustrate embodiments describedherein. FIG. 1A is a cross-sectional representation (see section cutX′-X′ of FIG. 1C) of an electrochromic lite 100, which is fabricatedstarting with a glass sheet 105. FIG. 1B shows an end view (see viewingperspective Y-Y′ of FIG. 1C) of electrochromic lite 100, and FIG. 1Cshows a top-down view of electrochromic lite 100. FIG. 1A shows theelectrochromic lite after fabrication on glass sheet 105, edge deletedto produce area 140, around the perimeter of the lite. Theelectrochromic lite has also been laser scribed and bus bars have beenattached. The glass lite 105 has a diffusion barrier 110, and a firsttransparent conducting oxide layer (TCO) 115, on the diffusion barrier.In this example, the edge deletion process removes both TCO 115 anddiffusion barrier 110, but in other embodiments only the TCO is removed,leaving the diffusion barrier intact. The TCO 115 is the first of twoconductive layers used to form the electrodes of the electrochromicdevice fabricated on the glass sheet. In this example, the glass sheetincludes underlying glass and the diffusion barrier layer. Thus, in thisexample, the diffusion barrier is formed, and then the first TCO, anelectrochromic stack 125, (e.g., having electrochromic, ion conductor,and counter electrode layers), and a second TCO 130, are formed. In oneembodiment, the electrochromic device (electrochromic stack and secondTCO) is fabricated in an integrated deposition system where the glasssheet does not leave the integrated deposition system at any time duringfabrication of the stack. In one embodiment, the first TCO layer is alsoformed using the integrated deposition system where the glass sheet doesnot leave the integrated deposition system during deposition of theelectrochromic stack and the (second) TCO layer. In one embodiment, allof the layers (diffusion barrier, first TCO, electrochromic stack, andsecond TCO) are deposited in the integrated deposition system where theglass sheet does not leave the integrated deposition system duringdeposition. In this example, prior to deposition of electrochromic stack125, an isolation trench 120, is cut through TCO 115 and diffusionbarrier 110. Trench 120 is made in contemplation of electricallyisolating an area of TCO 115 that will reside under bus bar 1 afterfabrication is complete (see FIG. 1A). This is done to avoid chargebuildup and coloration of the electrochromic device under the bus bar,which can be undesirable.

After formation of the electrochromic device, edge deletion processesand additional laser scribing are performed. FIG. 1A depicts areas 140where the device has been removed, in this example, from a perimeterregion surrounding laser scribe trenches 150, 155, 160, and 165.Trenches 150, 160 and 165 pass through the electrochromic stack and alsothrough the first TCO and diffusion barrier. Trench 155 passes throughsecond TCO 130 and the electrochromic stack, but not the first TCO 115.Laser scribe trenches 150, 155, 160, and 165 are made to isolateportions of the electrochromic device, 135, 145, 170, and 175, whichwere potentially damaged during edge deletion processes from theoperable electrochromic device. In this example, laser scribe trenches150, 160, and 165 pass through the first TCO to aid in isolation of thedevice (laser scribe trench 155 does not pass through the first TCO,otherwise it would cut off bus bar 2's electrical communication with thefirst TCO and thus the electrochromic stack). The laser or lasers usedfor the laser scribe processes are typically, but not necessarily,pulse-type lasers, for example, diode-pumped solid state lasers. Forexample, the laser scribe processes can be performed using a suitablelaser from IPG Photonics (of Oxford, Mass.), or from Ekspla (of Vilnius,Lithuania). Scribing can also be performed mechanically, for example, bya diamond tipped scribe. One of ordinary skill in the art wouldappreciate that the laser scribing processes can be performed atdifferent depths and/or performed in a single process whereby the lasercutting depth is varied, or not, during a continuous path around theperimeter of the electrochromic device. In one embodiment, the edgedeletion is performed to the depth of the first TCO.

After laser scribing is complete, bus bars are attached. Non-penetratingbus bar 1 is applied to the second TCO. Non-penetrating bus bar 2 isapplied to an area where the device was not deposited (e.g., from a maskprotecting the first TCO from device deposition), in contact with thefirst TCO or, in this example, where an edge deletion process (e.g.,laser ablation using an apparatus having a XY or XYZ galvanometer) wasused to remove material down to the first TCO. In this example, both busbar 1 and bus bar 2 are non-penetrating bus bars. A penetrating bus baris one that is typically pressed into and through the electrochromicstack to make contact with the TCO at the bottom of the stack. Anon-penetrating bus bar is one that does not penetrate into theelectrochromic stack layers, but rather makes electrical and physicalcontact on the surface of a conductive layer, for example, a TCO.

The TCO layers can be electrically connected using a non-traditional busbar, for example, a bus bar fabricated with screen and lithographypatterning methods. In one embodiment, electrical communication isestablished with the device's transparent conducting layers via silkscreening (or using another patterning method) a conductive ink followedby heat curing or sintering the ink. Advantages to using the abovedescribed device configuration include simpler manufacturing, forexample, and less laser scribing than conventional techniques which usepenetrating bus bars.

After the bus bars are connected, the device is integrated into aninsulated glass unit (IGU), which includes, for example, wiring the busbars and the like. In some embodiments, one or both of the bus bars areinside the finished IGU, however in one embodiment one bus bar isoutside the seal of the IGU and one bus bar is inside the IGU. In theformer embodiment, area 140 is used to make the seal with one face ofthe spacer used to form the IGU. Thus, the wires or other connection tothe bus bars runs between the spacer and the glass. As many spacers aremade of metal, e.g., stainless steel, which is conductive, it isdesirable to take steps to avoid short circuiting due to electricalcommunication between the bus bar and connector thereto and the metalspacer.

As described above, after the bus bars are connected, the electrochromiclite is integrated into an IGU, which includes, for example, wiring forthe bus bars and the like. In the embodiments described herein, both ofthe bus bars are inside the primary seal of the finished IGU.

FIG. 2A shows a cross-sectional schematic diagram of the electrochromicwindow as described in relation to FIGS. 1A-1C integrated into an IGU200. A spacer 205 is used to separate the electrochromic lite from asecond lite 210. Second lite 210 in IGU 200 is a non-electrochromiclite, however, the embodiments disclosed herein are not so limited. Forexample, lite 210 can have an electrochromic device thereon and/or oneor more coatings such as low-E coatings and the like. Lite 201 can alsobe laminated glass, such as depicted in FIG. 2B (lite 201 is laminatedto reinforcing pane 230, via resin 235). Between spacer 205 and thefirst TCO layer of the electrochromic lite is a primary seal material215. This primary seal material is also between spacer 205 and secondglass lite 210. Around the perimeter of spacer 205 is a secondary seal220. Bus bar wiring/leads traverse the seals for connection to acontroller. Secondary seal 220 may be much thicker that depicted. Theseseals aid in keeping moisture out of an interior space 225, of the IGU.They also serve to prevent argon or other gas in the interior of the IGUfrom escaping.

FIG. 3A schematically depicts an electrochromic device 300, incross-section. Electrochromic device 300 includes a substrate 302, afirst conductive layer (CL) 304, an electrochromic layer (EC) 306, anion conducting layer (IC) 308, a counter electrode layer (CE) 310, and asecond conductive layer (CL) 314. Layers 304, 306, 308, 310, and 314 arecollectively referred to as an electrochromic stack 320. A voltagesource 316 operable to apply an electric potential across electrochromicstack 320 effects the transition of the electrochromic device from, forexample, a bleached state to a colored state (depicted). The order oflayers can be reversed with respect to the substrate.

Electrochromic devices having distinct layers as described can befabricated as all solid state devices and/or all inorganic deviceshaving low defectivity. Such devices and methods of fabricating them aredescribed in more detail in U.S. patent application Ser. No. 12/645,111,entitled “Fabrication of Low-Defectivity Electrochromic Devices,” filedon Dec. 22, 2009, and naming Mark Kozlowski et al. as inventors, and inU.S. patent application Ser. No. 12/645,159, entitled, “ElectrochromicDevices,” filed on Dec. 22, 2009 and naming Zhongchun Wang et al. asinventors, both of which are hereby incorporated by reference in theirentireties. It should be understood, however, that any one or more ofthe layers in the stack may contain some amount of organic material. Thesame can be said for liquids that may be present in one or more layersin small amounts. It should also be understood that solid state materialmay be deposited or otherwise formed by processes employing liquidcomponents such as certain processes employing sol-gels or chemicalvapor deposition.

Additionally, it should be understood that the reference to a transitionbetween a bleached state and colored state is non-limiting and suggestsonly one example, among many, of an electrochromic transition that maybe implemented. Unless otherwise specified herein (including theforegoing discussion), whenever reference is made to a bleached-coloredtransition, the corresponding device or process encompasses otheroptical state transitions such as non-reflective-reflective,transparent-opaque, etc. Further, the term “bleached” refers to anoptically neutral state, for example, uncolored, transparent, ortranslucent. Still further, unless specified otherwise herein, the“color” of an electrochromic transition is not limited to any particularwavelength or range of wavelengths. As understood by those of skill inthe art, the choice of appropriate electrochromic and counter electrodematerials governs the relevant optical transition.

In embodiments described herein, the electrochromic device reversiblycycles between a bleached state and a colored state. In some cases, whenthe device is in a bleached state, a potential is applied to theelectrochromic stack 320 such that available ions in the stack resideprimarily in the counter electrode 310. When the potential on theelectrochromic stack is reversed, the ions are transported across theion conducting layer 308 to the electrochromic material 306 and causethe material to transition to the colored state. In a similar way, theelectrochromic device of embodiments described herein can be reversiblycycled between different tint levels (e.g., bleached state, darkestcolored state, and intermediate levels between the bleached state andthe darkest colored state).

Referring again to FIG. 3A, voltage source 316 may be configured tooperate in conjunction with radiant and other environmental sensors. Asdescribed herein, voltage source 316 interfaces with a device controller(not shown in this figure). Additionally, voltage source 316 mayinterface with an energy management system that controls theelectrochromic device according to various criteria such as the time ofyear, time of day, and measured environmental conditions. Such an energymanagement system, in conjunction with large area electrochromic devices(e.g., an electrochromic window), can dramatically lower the energyconsumption of a building.

Any material having suitable optical, electrical, thermal, andmechanical properties may be used as substrate 302. Such substratesinclude, for example, glass, plastic, and mirror materials. Suitableglasses include either clear or tinted soda lime glass, including sodalime float glass. The glass may be tempered or untempered.

In many cases, the substrate is a glass pane sized for residentialwindow applications. The size of such glass pane can vary widelydepending on the specific needs of the residence. In other cases, thesubstrate is architectural glass. Architectural glass is typically usedin commercial buildings, but may also be used in residential buildings,and typically, though not necessarily, separates an indoor environmentfrom an outdoor environment. In certain embodiments, architectural glassis at least 20 inches by 20 inches, and can be much larger, for example,as large as about 80 inches by 120 inches. Architectural glass istypically at least about 2 mm thick, typically between about 3 mm andabout 6 mm thick. Of course, electrochromic devices are scalable tosubstrates smaller or larger than architectural glass. Further, theelectrochromic device may be provided on a mirror of any size and shape.

On top of substrate 302 is conductive layer 304. In certain embodiments,one or both of the conductive layers 304 and 314 is inorganic and/orsolid. Conductive layers 304 and 314 may be made from a number ofdifferent materials, including conductive oxides, thin metalliccoatings, conductive metal nitrides, and composite conductors.Typically, conductive layers 304 and 314 are transparent at least in therange of wavelengths where electrochromism is exhibited by theelectrochromic layer. Transparent conductive oxides include metal oxidesand metal oxides doped with one or more metals. Examples of such metaloxides and doped metal oxides include indium oxide, indium tin oxide,doped indium oxide, tin oxide, doped tin oxide, zinc oxide, aluminumzinc oxide, doped zinc oxide, ruthenium oxide, doped ruthenium oxide andthe like. Since oxides are often used for these layers, they aresometimes referred to as “transparent conductive oxide” (TCO) layers.Thin metallic coatings that are substantially transparent may also beused.

The function of the conductive layers is to spread an electric potentialprovided by voltage source 316 over surfaces of the electrochromic stack320 to interior regions of the stack, with relatively little ohmicpotential drop. The electric potential is transferred to the conductivelayers though electrical connections to the conductive layers. In someembodiments, bus bars, one in contact with conductive layer 304 and onein contact with conductive layer 314, provide the electric connectionbetween the voltage source 316 and the conductive layers 304 and 314.The conductive layers 304 and 314 may also be connected to the voltagesource 316 with other conventional means.

Overlaying conductive layer 304 is electrochromic layer 306. In someembodiments, electrochromic layer 306 is inorganic and/or solid. Theelectrochromic layer may contain any one or more of a number ofdifferent electrochromic materials, including metal oxides. Such metaloxides include tungsten oxide (WO3), molybdenum oxide (Mo03), niobiumoxide (Nb2O5), titanium oxide (TiO2), copper oxide (CuO), iridium oxide(Ir203), chromium oxide (Cr2O3), manganese oxide (Mn2O3), vanadium oxide(V2O5), nickel oxide (Ni2O3), cobalt oxide (Co2O3) and the like. Duringoperation, electrochromic layer 306 transfers ions to and receives ionsfrom counter electrode layer 310 to cause optical transitions.

Generally, the colorization (or change in any optical property—e.g.,absorbance, reflectance, and transmittance) of the electrochromicmaterial is caused by reversible ion insertion into the material (e.g.,intercalation) and a corresponding injection of a charge balancingelectron. Typically some fraction of the ions responsible for theoptical transition is irreversibly bound up in the electrochromicmaterial. Some or all of the irreversibly bound ions are used tocompensate “blind charge” in the material. In most electrochromicmaterials, suitable ions include lithium ions (Li+) and hydrogen ions(H+) (that is, protons). In some cases, however, other ions will besuitable. In various embodiments, lithium ions are used to produce theelectrochromic phenomena. Intercalation of lithium ions into tungstenoxide (WO3-y (0<y≦˜0.3)) causes the tungsten oxide to change fromtransparent (bleached state) to blue (colored state).

Referring again to FIG. 3A, in electrochromic stack 320, ion conductinglayer 308 is sandwiched between electrochromic layer 306 and counterelectrode layer 310. In some embodiments, counter electrode layer 310 isinorganic and/or solid. The counter electrode layer may comprise one ormore of a number of different materials that serve as a reservoir ofions when the electrochromic device is in the bleached state. During anelectrochromic transition initiated by, for example, application of anappropriate electric potential, the counter electrode layer transferssome or all of the ions it holds to the electrochromic layer, changingthe electrochromic layer to the colored state. Concurrently, in the caseof NiWO, the counter electrode layer colors with the loss of ions.

In some embodiments, suitable materials for the counter electrodecomplementary to WO3 include nickel oxide (NiO), nickel tungsten oxide(NiWO), nickel vanadium oxide, nickel chromium oxide, nickel aluminumoxide, nickel manganese oxide, nickel magnesium oxide, chromium oxide(Cr2O3), manganese oxide (MnO2), and Prussian blue.

When charge is removed from a counter electrode 310 made of nickeltungsten oxide (that is, ions are transported from counter electrode 310to electrochromic layer 306), the counter electrode layer willtransition from a transparent state to a colored state.

In the depicted electrochromic device, between electrochromic layer 306and counter electrode layer 310, there is the ion conducting layer 308.Ion conducting layer 308 serves as a medium through which ions aretransported (in the manner of an electrolyte) when the electrochromicdevice transitions between the bleached state and the colored state.Preferably, ion conducting layer 308 is highly conductive to therelevant ions for the electrochromic and the counter electrode layers,but has sufficiently low electron conductivity that negligible electrontransfer takes place during normal operation. A thin ion conductinglayer with high ionic conductivity permits fast ion conduction and hencefast switching for high performance electrochromic devices. In certainembodiments, the ion conducting layer 308 is inorganic and/or solid.

Examples of suitable ion conducting layers (for electrochromic deviceshaving a distinct IC layer) include silicates, silicon oxides, tungstenoxides, tantalum oxides, niobium oxides, and borates. These materialsmay be doped with different dopants, including lithium. Lithium dopedsilicon oxides include lithium silicon-aluminum-oxide. In someembodiments, the ion conducting layer comprises a silicate-basedstructure. In some embodiments, a silicon-aluminum-oxide (SiAlO) is usedfor the ion conducting layer 308.

Electrochromic device 300 may include one or more additional layers (notshown), such as one or more passive layers. Passive layers used toimprove certain optical properties may be included in electrochromicdevice 300. Passive layers for providing moisture or scratch resistancemay also be included in electrochromic device 300. For example, theconductive layers may be treated with anti-reflective or protectiveoxide or nitride layers. Other passive layers may serve to hermeticallyseal electrochromic device 300.

FIG. 3B is a schematic cross-section of an electrochromic device in ableached state (or transitioning to a bleached state). In accordancewith specific embodiments, an electrochromic device 400 includes atungsten oxide electrochromic layer (EC) 406 and a nickel-tungsten oxidecounter electrode layer (CE) 410. Electrochromic device 400 alsoincludes a substrate 402, a conductive layer (CL) 404, an ion conductinglayer (IC) 408, and conductive layer (CL) 414.

A power source 416 is configured to apply a potential and/or current toan electrochromic stack 420 through suitable connections (e.g., busbars) to the conductive layers 404 and 414. In some embodiments, thevoltage source is configured to apply a potential of a few volts inorder to drive a transition of the device from one optical state toanother. The polarity of the potential as shown in FIG. 3A is such thatthe ions (lithium ions in this example) primarily reside (as indicatedby the dashed arrow) in nickel-tungsten oxide counter electrode layer410

FIG. 3C is a schematic cross-section of electrochromic device 400 shownin FIG. 3B but in a colored state (or transitioning to a colored state).In FIG. 3C, the polarity of voltage source 416 is reversed, so that theelectrochromic layer is made more negative to accept additional lithiumions, and thereby transition to the colored state. As indicated by thedashed arrow, lithium ions are transported across ion conducting layer408 to tungsten oxide electrochromic layer 406. Tungsten oxideelectrochromic layer 406 is shown in the colored state. Nickel-tungstenoxide counter electrode 410 is also shown in the colored state. Asexplained, nickel-tungsten oxide becomes progressively more opaque as itgives up (deintercalates) lithium ions. In this example, there is asynergistic effect where the transition to colored states for bothlayers 406 and 410 are additive toward reducing the amount of lighttransmitted through the stack and substrate.

As described above, an electrochromic device may include anelectrochromic (EC) electrode layer and a counter electrode (CE) layerseparated by an ionically conductive (IC) layer that is highlyconductive to ions and highly resistive to electrons. As conventionallyunderstood, the ionically conductive layer therefore prevents shortingbetween the electrochromic layer and the counter electrode layer. Theionically conductive layer allows the electrochromic and counterelectrodes to hold a charge and thereby maintain their bleached orcolored states. In electrochromic devices having distinct layers, thecomponents form a stack which includes the ion conducting layersandwiched between the electrochromic electrode layer and the counterelectrode layer. The boundaries between these three stack components aredefined by abrupt changes in composition and/or microstructure. Thus,the devices have three distinct layers with two abrupt interfaces.

In accordance with certain embodiments, the counter electrode andelectrochromic electrodes are formed immediately adjacent one another,sometimes in direct contact, without separately depositing an ionicallyconducting layer. In some embodiments, electrochromic devices having aninterfacial region rather than a distinct IC layer are employed. Suchdevices, and methods of fabricating them, are described in U.S. Pat. No.8,300,298 and U.S. patent application Ser. No. 12/772,075 filed on Apr.30, 2010, and U.S. patent application Ser. Nos. 12/814,277 and12/814,279, filed on Jun. 11, 2010—each of the three patent applicationsand patent is entitled “Electrochromic Devices,” each names ZhongchunWang et al. as inventors, and each is incorporated by reference hereinin its entirety.

II. Window Controllers

A window controller is used to control the tint level of theelectrochromic device of an electrochromic window. In some embodiments,the window controller is able to transition the electrochromic windowbetween two tint states (levels), a bleached state and a colored state.In other embodiments, the controller can additionally transition theelectrochromic window (e.g., having a single electrochromic device) tointermediate tint levels. In some disclosed embodiments, the windowcontroller is able to transition the electrochromic window to four ormore tint levels. Certain electrochromic windows allow intermediate tintlevels by using two (or more) electrochromic lites in a single IGU,where each lite is a two-state lite. This is described in reference toFIGS. 2A and 2B in this section.

As noted above with respect to FIGS. 2A and 2B, in some embodiments, anelectrochromic window can include an electrochromic device 400 on onelite of an IGU 200 and another electrochromic device 400 on the otherlite of the IGU 200. If the window controller is able to transition eachelectrochromic device between two states, a bleached state and a coloredstate, the electrochromic window is able to attain four different states(tint levels), a colored state with both electrochromic devices beingcolored, a first intermediate state with one electrochromic device beingcolored, a second intermediate state with the other electrochromicdevice being colored, and a bleached state with both electrochromicdevices being bleached. Embodiments of multi-pane electrochromic windowsare further described in U.S. Pat. No. 8,270,059, naming Robin Friedmanet al. as inventors, titled “MULTI-PANE ELECTROCHROMIC WINDOWS,” whichis hereby incorporated by reference in its entirety.

In some embodiments, the window controller is able to transition anelectrochromic window having an electrochromic device capable oftransitioning between two or more tint levels. For example, a windowcontroller may be able to transition the electrochromic window to ableached state, one or more intermediate levels, and a colored state. Insome other embodiments, the window controller is able to transition anelectrochromic window incorporating an electrochromic device between anynumber of tint levels between the bleached state and the colored state.Embodiments of methods and controllers for transitioning anelectrochromic window to an intermediate tint level or levels arefurther described in U.S. Pat. No. 8,254,013, naming Disha Mehtani etal. as inventors, titled “CONTROLLING TRANSITIONS IN OPTICALLYSWITCHABLE DEVICES,” which is hereby incorporated by reference in itsentirety.

In some embodiments, a window controller can power one or moreelectrochromic devices in an electrochromic window. Typically, thisfunction of the window controller is augmented with one or more otherfunctions described in more detail below. Window controllers describedherein are not limited to those that have the function of powering anelectrochromic device to which it is associated for the purposes ofcontrol. That is, the power source for the electrochromic window may beseparate from the window controller, where the controller has its ownpower source and directs application of power from the window powersource to the window. However, it is convenient to include a powersource with the window controller and to configure the controller topower the window directly, because it obviates the need for separatewiring for powering the electrochromic window.

Further, the window controllers described in this section are describedas standalone controllers which may be configured to control thefunctions of a single window or a plurality of electrochromic windows,without integration of the window controller into a building controlnetwork or a building management system (BMS). Window controllers,however, may be integrated into a building control network or a BMS, asdescribed further in the Building Management System section of thisdisclosure.

FIG. 4 depicts a block diagram of some components of a window controller450 and other components of a window controller system of disclosedembodiments. FIG. 4 is a simplified block diagram of a windowcontroller, and more detail regarding window controllers can be found inU.S. patent application Ser. Nos. 13/449,248 and 13/449,251, both namingStephen Brown as inventor, both titled “CONTROLLER FOROPTICALLY-SWITCHABLE WINDOWS,” and both filed on Apr. 17, 2012, and inU.S. patent Ser. No. 13/449,235, titled “CONTROLLING TRANSITIONS INOPTICALLY SWITCHABLE DEVICES,” naming Stephen Brown et al. as inventorsand filed on Apr. 17, 2012, all of which are hereby incorporated byreference in their entireties.

In FIG. 4, the illustrated components of the window controller 450include a window controller 450 having a microprocessor 455 or otherprocessor, a power width modulator (PWM) 460, a signal conditioningmodule 465, and a computer readable medium (e.g., memory) having aconfiguration file 475. Window controller 450 is in electroniccommunication with one or more electrochromic devices 400 in anelectrochromic window through network 480 (wired or wireless) to sendinstructions to the one or more electrochromic devices 400. In someembodiments, the window controller 450 may be a local window controllerin communication through a network (wired or wireless) to a masterwindow controller.

In disclosed embodiments, a building may have at least one room havingan electrochromic window between the exterior and interior of abuilding. One or more sensors may be located to the exterior of thebuilding and/or inside the room. In embodiments, the output from the oneor more sensors may be input to the signal conditioning module 465 ofthe window controller 450. In some cases, the output from the one ormore sensors may be input to a BMS, as described further in the BuildingManagement Systems section. Although the sensors of depicted embodimentsare shown as located on the outside vertical wall of the building, thisis for the sake of simplicity, and the sensors may be in otherlocations, such as inside the room or on other surfaces to the exterior,as well. In some cases, two or more sensors may be used to measure thesame input, which can provide redundancy in case one sensor fails or hasan otherwise erroneous reading.

FIG. 5 depicts a schematic diagram of a room 500 having anelectrochromic window 505 with at least one electrochromic device. Theelectrochromic window 505 is located between the exterior and theinterior of a building, which includes the room 500. The room 500 alsoincludes a window controller 450 connected to and configured to controlthe tint level of the electrochromic window 505. An exterior sensor 510is located on a vertical surface in the exterior of the building. Inother embodiments, an interior sensor may also be used to measure theambient light in room 500. In yet other embodiments, an occupant sensormay also be used to determine when an occupant is in the room 500.

Exterior sensor 510 is a device, such as a photosensor, that is able todetect radiant light incident upon the device flowing from a lightsource such as the sun or from light reflected to the sensor from asurface, particles in the atmosphere, clouds, etc. The exterior sensor510 may generate a signal in the form of electrical current that resultsfrom the photoelectric effect and the signal may be a function of thelight incident on the sensor 510. In some cases, the device may detectradiant light in terms of irradiance in units of watts/m² or othersimilar units. In other cases, the device may detect light in thevisible range of wavelengths in units of foot candles or similar units.In many cases, there is a linear relationship between these values ofirradiance and visible light.

Irradiance values from sunlight can be predicted based on the time ofday and time of year as the angle at which sunlight strikes the earthchanges. Exterior sensor 510 can detect radiant light in real-time,which accounts for reflected and obstructed light due to buildings,changes in weather (e.g., clouds), etc. For example, on cloudy days,sunlight would be blocked by the clouds and the radiant light detectedby an exterior sensor 510 would be lower than on cloudless days.

In some embodiments, there may be one or more exterior sensors 510associated with a single electrochromic window 505. Output from the oneor more exterior sensors 510 could be compared to one another todetermine, for example, if one of exterior sensors 510 is shaded by anobject, such as by a bird that landed on exterior sensor 510. In somecases, it may be desirable to use relatively few sensors in a buildingbecause some sensors can be unreliable and/or expensive. In certainimplementations, a single sensor or a few sensors may be employed todetermine the current level of radiant light from the sun impinging onthe building or perhaps one side of the building. A cloud may pass infront of the sun or a construction vehicle may park in front of thesetting sun. These will result in deviations from the amount of radiantlight from the sun calculated to normally impinge on the building.

Exterior sensor 510 may be a type of photosensor. For example, exteriorsensor 510 may be a charge coupled device (CCD), photodiode,photoresistor, or photovoltaic cell. One of ordinary skill in the artwould appreciate that future developments in photosensor and othersensor technology would also work, as they measure light intensity andprovide an electrical output representative of the light level.

In some embodiments, output from exterior sensor 510 may be input to thesignal conditioning module 465. The input may be in the form of avoltage signal to signal conditioning module 465. Signal conditioningmodule 465 passes an output signal to the window controller 450. Windowcontroller 450 determines a tint level of the electrochromic window 505,based on various information from the configuration file 475, outputfrom the signal conditioning module 465, override values. Windowcontroller 450 and then instructs the PWM 460, to apply a voltage and/orcurrent to electrochromic window 505 to transition to the desired tintlevel.

In disclosed embodiments, window controller 450 can instruct the PWM460, to apply a voltage and/or current to electrochromic window 505 totransition it to any one of four or more different tint levels. Indisclosed embodiments, electrochromic window 505 can be transitioned toat least eight different tint levels described as: 0 (lightest), 5, 10,15, 20, 25, 30, and 35 (darkest). The tint levels may linearlycorrespond to visual transmittance values and solar gain heatcoefficient (SGHC) values of light transmitted through theelectrochromic window 505. For example, using the above eight tintlevels, the lightest tint level of 0 may correspond to an SGHC value of0.80, the tint level of 5 may correspond to an SGHC value of 0.70, thetint level of 10 may correspond to an SGHC value of 0.60, the tint levelof 15 may correspond to an SGHC value of 0.50, the tint level of 20 maycorrespond to an SGHC value of 0.40, the tint level of 25 may correspondto an SGHC value of 0.30, the tint level of 30 may correspond to an SGHCvalue of 0.20, and the tint level of 35 (darkest) may correspond to anSGHC value of 0.10.

Window controller 450 or a master controller in communication with thewindow controller 450 may employ any one or more predictive controllogic components to determine a desired tint level based on signals fromthe exterior sensor 510 and/or other input. The window controller 450can instruct the PWM 460 to apply a voltage and/or current toelectrochromic window 505 to transition it to the desired tint level.

III. An example of Predictive Control Logic

In disclosed embodiments, predictive control logic is used to implementmethods of determining and controlling a desired tint level for theelectrochromic window 505 or other tintable window that accounts foroccupant comfort and/or energy conservation considerations. Thispredictive control logic may employ one or more logic modules. FIGS.6A-6C include diagrams depicting some information collected by each ofthree logic modules A, B, and C of an exemplary control logic ofdisclosed embodiments.

FIG. 6A shows the penetration depth of direct sunlight into a room 500through an electrochromic window 505 between the exterior and theinterior of a building, which includes the room 500. Penetration depthis a measure of how far direct sunlight will penetrate into the room500. As shown, penetration depth is measured in a horizontal directionaway from the sill (bottom) of window. Generally, the window defines anaperture that provides an acceptance angle for direct sunlight. Thepenetration depth is calculated based upon the geometry of the window(e.g., window dimensions), its position and orientation in the room, anyfins or other exterior shading outside of the window, and the positionof the sun (e.g. angle of direct sunlight for a particular time of dayand date). Exterior shading to an electrochromic window 505 may be dueto any type of structure that can shade the window such as an overhang,a fin, etc. In FIG. 6A, there is an overhang 520 above theelectrochromic window 505 that blocks a portion of the direct sunlightentering the room 500 thus shortening the penetration depth. The room500 also includes a local window controller 450 connected to andconfigured to control the tint level of the electrochromic window 505.An exterior sensor 510 is located on a vertical surface in the exteriorof the building.

Module A can be used to determine a tint level that considers occupantcomfort from direct sunlight through the electrochromic window 505 ontoan occupant or their activity area. The tint level is determined basedon a calculated penetration depth of direct sunlight into the room andthe space type (e.g., desk near window, lobby, etc.) in the room at aparticular instant in time. In some cases, the tint level may also bebased on providing sufficient natural lighting into the room. In manycases, the penetration depth is the value calculated at a time in thefuture to account for glass transition time. The concern addressed inModule A is that direct sunlight may penetrate so deep into the room 500as to show directly on an occupant working at a desk or other worksurface in a room. Publicly available programs can provide calculationof the sun's position and allow for easy calculation of penetrationdepth.

FIG. 6A also shows a desk in the room 500 as an example of a space typeassociated with an activity area (i.e. desk) and location of theactivity area (i.e. location of desk). Each space type is associatedwith different tint levels for occupant comfort. For example, if theactivity is a critical activity such as work in an office being done ata desk or computer, and the desk is located near the window, the desiredtint level may be higher than if the desk were further away from thewindow. As another example, if the activity is non-critical, such as theactivity in a lobby, the desired tint level may be lower than for thesame space having a desk.

FIG. 6B shows direct sunlight and radiation under clear sky conditionsentering the room 500 through the electrochromic window 505. Theradiation may be from sunlight scattered by molecules and particles inthe atmosphere. Module B determines a tint level based on predictedvalues of irradiance under clear sky conditions flowing through theelectrochromic window 505 under consideration. Various software, such asopen source RADIANCE program, can be used to predict clear skyirradiance at a certain latitude, longitude, time of year, and time ofday, and for a given window orientation.

FIG. 6C shows radiant light from the sky that is measured in real-timeby an exterior sensor 510 to account for light that may be obstructed byor reflected from objects such as buildings or weather conditions (e.g.,clouds) that are not accounted for in the clear sky predictions. Thetint level determined by Module C is based on the real-time irradiancebased on measurements taken by the exterior sensor 510.

The predictive control logic may implement one or more of the logicModules A, B and C separately for each electrochromic window 505 in thebuilding. Each electrochromic window 505 can have a unique set ofdimensions, orientation (e.g., vertical, horizontal, tilted at anangle), position, associated space type, etc. A configuration file withthis information and other information can be maintained for eachelectrochromic window 505. The configuration file 475 may be stored inthe computer readable medium 470 of the local window controller 450 ofthe electrochromic window 505 or in the BMS described later in thisdisclosure. The configuration file 475 can include information such as awindow configuration, an occupancy lookup table, information about anassociated datum glass, and/or other data used by the predictive controllogic. The window configuration may include information such as thedimensions of the electrochromic window 505, the orientation of theelectrochromic window 505, the position of the electrochromic window505, etc.

A lookup table describes tint levels that provide occupant comfort forcertain space types and penetration depths. That is, the tint levels inthe occupancy lookup table are designed to provide comfort tooccupant(s) that may be in the room 500 from direct sunlight on theoccupant(s) or their workspace. An example of an occupancy lookup tableis shown in FIG. 10.

The space type is a measure to determine how much tinting will berequired to address occupant comfort concerns for a given penetrationdepth and/or provide comfortable natural lighting in the room. The spacetype parameter may take into consideration many factors. Among thesefactors is the type of work or other activity being conducted in aparticular room and the location of the activity. Close work associatedwith detailed study requiring great attention might be at one spacetype, while a lounge or a conference room might have a different spacetype. Additionally, the position of the desk or other work surface inthe room with respect to the window is a consideration in defining thespace type. For example, the space type may be associated with an officeof a single occupant having a desk or other workspace located near theelectrochromic window 505. As another example, the space type may be alobby.

In certain embodiments, one or more modules of the predictive controllogic can determine desired tint levels while accounting for energyconservation in addition to occupant comfort. These modules maydetermine energy savings associated with a particular tint level bycomparing the performance of the electrochromic window 505 at that tintlevel to a datum glass or other standard reference window. The purposeof using this reference window can be to ensure that the predictivecontrol logic conforms to requirements of the municipal building code orother requirements for reference windows used in the locale of thebuilding. Often municipalities define reference windows usingconventional low emissivity glass to control the amount of airconditioning load in the building. As an example of how the referencewindow 505 fits into the predictive control logic, the logic may bedesigned so that the irradiance coming through a given electrochromicwindow 505 is never greater than the maximum irradiance coming through areference window as specified by the respective municipality. Indisclosed embodiments, predictive control logic may use the solar heatgain coefficient (SHGC) value of the electrochromic window 505 at aparticular tint level and the SHGC of the reference window to determinethe energy savings of using the tint level. Generally, the value of theSHGC is the fraction of incident light of all wavelengths transmittedthrough the window. Although a datum glass is described in manyembodiments, other standard reference windows can be used. Generally theSHGC of the reference window (e.g., datum glass) is a variable that canbe different for different geographical locations and windoworientations, and is based on code requirements specified by therespective municipality.

Generally, buildings are designed to have an HVAC with the capacity tofulfill the maximum expected heating and/or air-conditioning loadsrequired at any given instance. The calculation of required capacity maytake into consideration the datum glass or reference window required ina building at the particular location where the building is beingconstructed. Therefore, it is important that the predictive controllogic meet or exceed the functional requirements of the datum glass inorder to allow building designers to confidently determine how much HVACcapacity to put into a particular building. Since the predictive controllogic can be used to tint the window to provide additional energysavings over the datum glass, the predictive control logic could beuseful in allowing building designers to have a lower HVAC capacity thanwould have been required using the datum glass specified by the codesand standards.

Particular embodiments described herein assume that energy conservationis achieved by reducing air conditioning load in a building. Therefore,many of the implementations attempt to achieve the maximum tintingpossible, while accounting for occupant comfort level and perhapslighting load in a room having with the window under consideration.However, in some climates, such as those at far northern and forsouthern latitudes, heating may be more of a concern than airconditioning. Therefore, the predictive control logic can be modified,specifically, road reversed in some matters, so that less tinting occursin order to ensure that the heating load of the building is reduced.

In certain implementations, the predictive control logic has only twoindependent variables that can be controlled by an occupant (end user),building designer, or building operator. These are the space types for agiven window and the datum glass associated with the given window. Oftenthe datum glass is specified when the predictive control logic isimplemented for a given building. The space type can vary, but istypically static. In certain implementations, the space type may be partof the configuration file maintained by the building or stored in thelocal window controller 450. In some cases, the configuration file maybe updated to account for various changes in the building. For example,if there is a change in the space type (e.g., desk moved in an office,addition of desk, lobby changed into office area, wall moved, etc.) inthe building, an updated configuration file with a modified occupancylookup table may be stored in the computer readable medium 470. Asanother example, if an occupant is hitting manual override repeatedly,then the configuration file may be updated to reflect the manualoverride.

FIG. 7 is a flowchart showing predictive control logic for a method ofcontrolling one or more electrochromic windows 505 in a building,according to embodiments. The predictive control logic uses one or moreof the Modules A, B, and C to calculate tint levels for the window(s)and sends instructions to transition the window(s). The calculations inthe control logic are run 1 to n times at intervals timed by the timerat step 610. For example, the tint level can be recalculated 1 to ntimes by one or more of the Modules A, B, and C and calculated forinstances in time t_(i)=t₁, t₂ . . . t_(n). n is the number ofrecalculations performed and n can be at least 1. The logic calculationscan be done at constant time intervals in some cases. In one cases, thelogic calculations may be done every 2 to 5 minutes. However, tinttransition for large pieces of electrochromic glass can take up to 30minutes or more. For these large windows, calculations may be done on aless frequent basis such as every 30 minutes.

At step 620, logic Modules A, B, and C perform calculations to determinea tint level for each electrochromic window 505 at a single instant intime t_(i). These calculations can be performed by the window controller450. In certain embodiments, the predictive control logic predictivelycalculates how the window should transition in advance of the actualtransition. In these cases, the calculations in Modules A, B, and C canbe based on a future time around or after transition is complete. Inthese cases, the future time used in the calculations may be a time inthe future that is sufficient to allow the transition to be completedafter receiving the tint instructions. In these cases, the controllercan send tint instructions in the present time in advance of the actualtransition. By the completion of the transition, the window will havetransitioned to a tint level that is desired for that time.

At step 630, the predictive control logic allows for certain types ofoverrides that disengage the algorithm at Modules A, B, and C and defineoverride tint levels at step 640 based on some other consideration. Onetype of override is a manual override. This is an override implementedby an end user who is occupying a room and determines that a particulartint level (override value) is desirable. There may be situations wherethe user's manual override is itself overridden. An example of anoverride is a high demand (or peak load) override, which is associatedwith a requirement of a utility that energy consumption in the buildingbe reduced. For example, on particularly hot days in large metropolitanareas, it may be necessary to reduce energy consumption throughout themunicipality in order to not overly tax the municipality's energygeneration and delivery systems. In such cases, the building mayoverride the tint level from the predictive control logic describedherein to ensure that all windows have a particularly high level oftinting. Another example of an override may be if there is no occupantin the room example weekend sin a commercial office building. In thesecases, the building may disengage one or more Modules that relate tooccupant comfort and all the windows may have a high level of tinting incold weather and low level of tinting in warm weather.

At step 650, the tint levels are transmitted over a network toelectrochromic device(s) in one or more electrochromic windows 505 inthe building. In certain embodiments, the transmission of tint levels toall windows of a building may be implemented with efficiency in mind.For example, if the recalculation of tint level suggests that no changein tint from the current tint level is required, then there is notransmission of instructions with an updated tint level. As anotherexample, the building may be divided into zones based on window size.The predictive control logic may recalculate tint levels for zones withsmaller windows more frequently than for zones with larger windows.

In some embodiments, the logic in FIG. 7 for implementing the controlmethods for multiple electrochromic windows 505 in an entire buildingcan be on a single device, for example, a single master windowcontroller. This device can perform the calculations for each and everywindow in the building and also provide an interface for transmittingtint levels to one or more electrochromic devices in individualelectrochromic windows 505.

Also, there may be certain adaptive components of the predictive controllogic of embodiments. For example, the predictive control logic maydetermine how an end user (e.g. occupant) tries to override thealgorithm at particular times of day and makes use of this informationin a more predictive manner to determine desired tint levels. In onecase, the end user may be using a wall switch to override the tint levelprovided by the predictive logic at a certain time each day to anoverride value. The predictive control logic may receive informationabout these instances and change the predictive control logic to changethe tint level to the override value at that time of day.

FIG. 8 is a diagram showing a particular implementation of block 620from FIG. 7. This diagram shows a method of performing all three ModulesA, B, and C in sequence to calculate a final tint level of a particularelectrochromic window 505 for a single instant in time t_(i). The finaltint level may be the maximum permissible transmissivity of the windowunder consideration. FIG. 8 also includes some exemplary inputs andoutputs of Modules A, B, and C. The calculations in Modules A, B, and Care performed by window controller 450 in local window controller 450 inembodiments. In other embodiments, one or more of the modules can beperformed by another processor. Although illustrated embodiments showall three Modules A, B, and C being used, other embodiments may use oneor more of the Modules A, B, and C or may use additional modules.

At step 700, window controller 450 uses Module A to determine a tintlevel for occupant comfort to prevent direct glare from sunlightpenetrating the room 500. Window controller 450 uses Module A tocalculate the penetration depth of direct sunlight into the room 500based on the sun's position in the sky and the window configuration fromthe configuration file. The position of the sun is calculated based onthe latitude and longitude of the building and the time of day and date.The occupancy lookup table and space type are input from a configurationfile for the particular window. Module A outputs the Tint level from Ato Module B.

The goal of Module A is to ensure that direct sunlight or glare does notstrike the occupant or his or her workspace. The tint level from ModuleA is determined to accomplish this purpose. Subsequent calculations oftint level in Modules B and C can reduce energy consumption and mayrequire even greater tint. However, if subsequent calculations of tintlevel based on energy consumption suggest less tinting than required toavoid interfering with the occupant, the predictive logic prevents thecalculated greater level of transmissivity from being executed to assureoccupant comfort.

At step 800, the tint level calculated in Module A is input into ModuleB. A tint level is calculated based on predictions of irradiance underclear sky conditions (clear sky irradiance). Window controller 450 usesModule B to predict clear sky irradiance for the electrochromic window505 based on window orientation from the configuration file and based onlatitude and longitude of the building. These predictions are also basedon a time of day and date. Publicly available software such as theRADIANCE program, which is an open-source program, can provide thecalculations for predicting clear sky irradiance. The SHGC of the datumglass is also input into Module B from the configuration file. Windowcontroller 450 uses Module B to determine a tint level that is darkerthan the tint level in A and transmits less heat than the datum glass ispredicted to transmit under maximum clear sky irradiance. Maximum clearsky irradiance is the highest level of irradiance for all timespredicted for clear sky conditions.

At step 900, a tint level from B and predicted clear sky irradiance areinput to Module C. Real-time irradiance values are input to Module Cbased on measurements from an exterior sensor 510. Window controller 450uses Module C to calculate irradiance transmitted into the room if thewindow were tinted to the Tint level from Module B under clear skyconditions. Window controller 450 uses Module C to find the appropriatetint level where the actual irradiance through the window with this tintlevel is less than or equal to the irradiance through the window withthe Tint level from Module B. The tint level determined in Module C isthe final tint level.

Much of the information input to the predictive control logic isdetermined from fixed information about the latitude and longitude, timeand date. This information describes where the sun is with respect tothe building, and more particularly with respect to the window for whichthe predictive control logic is being implemented. The position of thesun with respect to the window provides information such as thepenetration depth of direct sunlight into the room assisted with thewindow. It also provides an indication of the maximum irradiance orsolar radiant energy flux coming through the window. This calculatedlevel of irradiance can be modified by sensor input which might indicatethat there is a reduction from the maximum amount of irradiance. Again,such reduction might be caused by a cloud or other obstruction betweenthe window and the sun.

FIG. 9 is a flowchart showing details of step 700 of FIG. 8. At step705, Module A begins. At step 710, the window controller 450 uses ModuleA to calculate the position of the sun for the latitude and longitudecoordinates of the building and the date and time of day of a particularinstant in time, t_(i). The latitude and longitude coordinates may beinput from the configuration file. The date and time of day may be basedon the current time provided by the timer. The sun position iscalculated at the particular instant in time, t_(i), which may be in thefuture in some cases. In other embodiments, the position of the sun iscalculated in another component (e.g., module) of the predictive controllogic.

At step 720, window controller 450 uses Module A to calculate thepenetration depth of direct sunlight into the room 500 at the particularinstant in time used in step 710. Module A calculates the penetrationdepth based on the calculated position of the sun and windowconfiguration information including the position of the window,dimensions of the window, orientation of the window (i.e. directionfacing), and the details of any exterior shading. The windowconfiguration information is input from the configuration fileassociated with the electrochromic window 505. For example, Module A canbe used to calculate the penetration depth of the vertical window shownin FIG. 6A by first calculating the angle θ of the direct sunlight basedon the position of the sun calculated at the particular instant in time.The penetration depth can be determined based on calculated angle θ andthe location of the lintel (top of the window).

At step 730, a tint level is determined that will provide occupantcomfort for the penetration depth calculated in step 720. The occupancylookup table is used to find a desired tint level for the space typeassociated with the window, for the calculated penetration depth, andfor the acceptance angle of the window. The space type and occupancylookup table are provided as input from the configuration file for theparticular window.

An example of an occupancy lookup table is provided in FIG. 10. Thevalues in the table are in terms of a Tint level and associated SGHCvalues in parenthesis. FIG. 10 shows the different tint levels (SGHCvalues) for different combinations of calculated penetration values andspace types. The table is based on eight tint levels including 0(lightest), 5, 10, 15, 20, 25, 30, and 35 (lightest). The lightest tintlevel of 0 corresponds to an SGHC value of 0.80, the tint level of 5corresponds to an SGHC value of 0.70, the tint level of 10 correspondsto an SGHC value of 0.60, the tint level of 15 corresponds to an SGHCvalue of 0.50, the tint level of 20 corresponds to an SGHC value of0.40, the tint level of 25 corresponds to an SGHC value of 0.30, thetint level of 30 corresponds to an SGHC value of 0.20, and the tintlevel of 35 (darkest) corresponds to an SGHC value of 0.10. Theillustrated example includes three space types: Desk 1, Desk 2, andLobby and six penetration depths. FIG. 11A shows the location of Desk 1in the room 500. FIG. 11B shows the location of Desk 2 in the room 500.As shown in the occupancy lookup table of FIG. 10, the tint levels forDesk 1 close to the window are higher than the tint levels for Desk 2far from window to prevent glare when the desk is closer to the window.Occupancy lookup tables with other values may be used in otherembodiments. For example, one other occupancy lookup table may includeonly four tint levels associated with the penetration values. Anotherexample of an occupancy table with four tint levels associated with fourpenetration depths is shown in FIG. 20.

FIG. 12 is a diagram showing further detail of step 800 of FIG. 8. Atstep 805, Module B begins. At step 810, Module B can be used to predictthe irradiance at the window under clear sky conditions at t_(i). Thisclear sky irradiance at t_(i) is predicted based on the latitude andlongitude coordinates of the building and the window orientation (i.e.direction the window is facing). At step 820, the Maximum Clear SkyIrradiance incident the window at all times is predicted. Thesepredicted values of clear sky irradiance can be calculated using opensource software, such as Radiance.

At step 830, the window controller 450 uses Module B to determine themaximum amount of irradiance that would be transmitted through a datumglass into the room 500 at that time (i.e. determines Maximum DatumInside Irradiance). The calculated Maximum Clear Sky Irradiance fromstep 820 and the datum glass SHGC value from the configuration file canbe used to calculate the Maximum Irradiance inside the space using theequation: Maximum Datum Inside Irradiance=Datum Glass SHGC×Maximum ClearSky Irradiance.

At step 840, window controller 450 uses Module B to determine insideirradiance into the room 500 having a window with the current tint levelbased on the equation. The calculated Clear Sky Irradiance from step 810and the SHGC value associated with the current tint level can be used tocalculate the value of the inside irradiance using the equation: Tintlevel Irradiance=Tint level SHGC×Clear Sky Irradiance.

In one embodiment, one or more the steps 705, 810 and 820 may beperformed by a solar position calculator separate from Modules A and B.A solar position calculator refers to logic that determines the positionof the sun at a particular future time and makes predictivedeterminations (e.g., predicts clear sky irradiance) based on the sun'sposition at that future time. The solar position calculator may performone or more steps of the methods disclosed herein. The solar positioncalculator may be a portion of the predictive control logic performed byone or more of the components of the master window controller (e.g.,master window controller 1402 depicted in FIG. 17). For example, thesolar position calculator may be part of the predictive control logicshown in FIG. 18 implemented by the window controller 1410 (shown inFIG. 17).

At step 850, window controller 450 uses Module B to determine whetherthe inside irradiance based on the current tint level is less than orequal to the maximum datum inside irradiance and the tint level isdarker than the tint level from A. If the determination is NO, thecurrent tint level is incrementally increased (darkened) at step 860 andthe inside irradiance is recalculated at step 840. If the determinationis YES at step 850, Module B ends.

FIG. 13 is a diagram showing further detail of step 900 of FIG. 8. Atstep 905, Module C begins. A tint level from B and predicted clear skyirradiance at the instant in time t_(i) is input from Module B.Real-time irradiance values are input to Module C based on measurementsfrom an exterior sensor 510.

At step 910, window controller 450 uses Module C to calculate irradiancetransmitted into the room through an electrochromic window 505 tinted tothe Tint level from B under clear sky conditions. This Calculated InsideIrradiance can be determined using the equation: Calculated InsideIrradiance=SHGC of Tint Level from B×Predicted Clear Sky Irradiance fromB.

At step 920, window controller 450 uses Module C to find the appropriatetint level where the actual irradiance (=SR×Tint level SHGC) through thewindow with this tint level is less than or equal to the irradiancethrough the window with the Tint level from B (i.e. Actual InsideIrradiance≦Calculated Inside Irradiance). In some cases, the modulelogic starts with the tint level from B and incrementally increases thetint level until the Actual Inside Irradiance≦Calculated InsideIrradiance. The tint level determined in Module C is the final tintlevel. This final tint level may be transmitted in tint instructionsover the network to the electrochromic device(s) in the electrochromicwindow 505.

FIG. 14 is a diagram includes another implementation of block 620 fromFIG. 7. This diagram shows a method of performing Modules A, B, and C ofembodiments. In this method, the position of the sun is calculated basedon the latitude and longitude coordinates of the building for a singleinstant in time t_(i). The penetration depth is calculated in Module Abased on the window configuration including a position of the window,dimensions of the window, orientation of the window, and informationabout any external shading. Module A uses a lookup table to determinethe tint level from A based on the calculated penetration and the spacetype. The tint level from A is then input into Module B.

A program such as the open source program Radiance, is used to determineclear sky irradiance based on window orientation and latitude andlongitude coordinates of the building for both a single instant in timet_(i) and a maximum value for all times. The datum glass SHGC andcalculated maximum clear sky irradiance are input into Module B. ModuleB increases the tint level calculated in Module A in steps and picks atint level where the Inside radiation is less than or equal to the DatumInside Irradiance where: Inside Irradiance=Tint level SHGC×Clear SkyIrradiance and Datum Inside Irradiance=Datum SHGC×Maximum Clear SkyIrradiance. However, when Module A calculates the maximum tint of theglass, module B doesn't change the tint to make it lighter. The tintlevel calculated in B is then input into Module C. The predicted clearsky irradiance is also input into Module C.

Module C calculates the inside irradiance in the room with anelectrochromic window 505 having the tint level from B using theequation: Calculated Inside Irradiance=SHGC of Tint Level fromB×Predicted Clear Sky Irradiance from B. Module C then finds theappropriate tint level that meets the condition where actual insideirradiance is less than or equal to the Calculated Inside Irradiance.The actual inside irradiance is determined using the equation: ActualInside Irradiance=SR×Tint level SHGC. The tint level determined byModule C is the final tint level in tint instructions sent to theelectrochromic window 505.

IV. Building Management Systems (BMSs)

The window controllers described herein also are suited for integrationwith a BMS. A BMS is a computer-based control system installed in abuilding that monitors and controls the building's mechanical andelectrical equipment such as ventilation, lighting, power systems,elevators, fire systems, and security systems. A BMS consists ofhardware, including interconnections by communication channels to acomputer or computers, and associated software for maintainingconditions in the building according to preferences set by the occupantsand/or by the building manager. For example, a BMS may be implementedusing a local area network, such as Ethernet. The software can be basedon, for example, internet protocols and/or open standards. One exampleof software is software from Tridium, Inc. (of Richmond, Va.). Onecommunications protocol commonly used with a BMS is BACnet (buildingautomation and control networks).

A BMS is most common in a large building, and typically functions atleast to control the environment within the building. For example, a BMSmay control temperature, carbon dioxide levels, and humidity within abuilding. Typically, there are many mechanical devices that arecontrolled by a BMS such as heaters, air conditioners, blowers, vents,and the like. To control the building environment, a BMS may turn on andoff these various devices under defined conditions. A core function of atypical modern BMS is to maintain a comfortable environment for thebuilding's occupants while minimizing heating and cooling costs/demand.Thus, a modern BMS is used not only to monitor and control, but also tooptimize the synergy between various systems, for example, to conserveenergy and lower building operation costs.

In some embodiments, a window controller is integrated with a BMS, wherethe window controller is configured to control one or moreelectrochromic windows 505 or other tintable windows. In one embodiment,the one or more electrochromic windows include at least one all solidstate and inorganic electrochromic device. In one embodiment, the one ormore electrochromic windows include only all solid state and inorganicwindows. In one embodiment, the electrochromic windows are multistateelectrochromic windows, as described in U.S. patent application Ser. No.12/851,514, filed on Aug. 5, 2010, and entitled “MultipaneElectrochromic Windows.”

FIG. 15 depicts a schematic diagram of an embodiment of a BMS 1100, thatmanages a number of systems of a building 1101, including securitysystems, heating/ventilation/air conditioning (HVAC), lighting of thebuilding, power systems, elevators, fire systems, and the like. Securitysystems may include magnetic card access, turnstiles, solenoid drivendoor locks, surveillance cameras, burglar alarms, metal detectors, andthe like. Fire systems may include fire alarms and fire suppressionsystems including a water plumbing control. Lighting systems may includeinterior lighting, exterior lighting, emergency warning lights,emergency exit signs, and emergency floor egress lighting. Power systemsmay include the main power, backup power generators, and uninterruptedpower source (UPS) grids.

Also, BMS 1100 manages a master window controller 1102. In this example,master window controller 1102 is depicted as a distributed network ofwindow controllers including a master network controller, 1103,intermediate network controllers, 1105 a and 1105 b, and end or leafcontrollers 1110. End or leaf controllers 1110 may be similar to windowcontroller 450 described with respect to FIG. 4. For example, masternetwork controller 1103 may be in proximity to the BMS 1100, and eachfloor of building 1101 may have one or more intermediate networkcontrollers 1105 a and 1105 b, while each window of the building has itsown end controller 1110. In this example, each of controllers 1110controls a specific electrochromic window of building 1101.

Each of controllers 1110 can be in a separate location from theelectrochromic window that it controls, or be integrated into theelectrochromic window. For simplicity, only ten electrochromic windowsof building 1101 are depicted as controlled by master window controller1102. In a typical setting there may be a large number of electrochromicwindows in a building controlled by master window controller 1102.Master window controller 1102 need not be a distributed network ofwindow controllers. For example, a single end controller which controlsthe functions of a single electrochromic window also falls within thescope of the embodiments disclosed herein, as described above.Advantages and features of incorporating electrochromic windowcontrollers as described herein with BMSs are described below in moredetail and in relation to FIG. 15, where appropriate.

One aspect of the disclosed embodiments is a BMS including amultipurpose electrochromic window controller as described herein. Byincorporating feedback from a electrochromic window controller, a BMScan provide, for example, enhanced: 1) environmental control, 2) energysavings, 3) security, 4) flexibility in control options, 5) improvedreliability and usable life of other systems due to less reliancethereon and therefore less maintenance thereof, 6) informationavailability and diagnostics, 7) effective use of staff, and variouscombinations of these, because the electrochromic windows can beautomatically controlled.

In some embodiments, a BMS may not be present or a BMS may be presentbut may not communicate with a master network controller or communicateat a high level with a master network controller. In some embodiments, amaster network controller can provide, for example, enhanced: 1)environmental control, 2) energy savings, 3) flexibility in controloptions, 4) improved reliability and usable life of other systems due toless reliance thereon and therefore less maintenance thereof, 5)information availability and diagnostics, 6) effective use of staff, andvarious combinations of these, because the electrochromic windows can beautomatically controlled. In these embodiments, maintenance on the BMSwould not interrupt control of the electrochromic windows.

FIG. 16 depicts a block diagram of an embodiment of a building network1200 for a building. As noted above, network 1200 may employ any numberof different communication protocols, including BACnet. As shown,building network 1200 includes a master network controller 1205, alighting control panel 1210, a building management system (BMS) 1215, asecurity control system, 1220, and a user console, 1225. These differentcontrollers and systems in the building may be used to receive inputfrom and/or control a HVAC system 1230, lights 1235, security sensors1240, door locks 1245, cameras 1250, and tintable windows 1255, of thebuilding.

Master network controller 1205 may function in a similar manner asmaster network controller 1103 described with respect to FIG. 15.Lighting control panel 1210 may include circuits to control the interiorlighting, the exterior lighting, the emergency warning lights, theemergency exit signs, and the emergency floor egress lighting. Lightingcontrol panel 1210 also may include occupancy sensors in the rooms ofthe building. BMS 1215 may include a computer server that receives datafrom and issues commands to the other systems and controllers of network1200. For example, BMS 1215 may receive data from and issue commands toeach of the master network controller 1205, lighting control panel 1210,and security control system 1220. Security control system 1220 mayinclude magnetic card access, turnstiles, solenoid driven door locks,surveillance cameras, burglar alarms, metal detectors, and the like.User console 1225 may be a computer terminal that can be used by thebuilding manager to schedule operations of, control, monitor, optimize,and troubleshoot the different systems of the building. Software fromTridium, Inc. may generate visual representations of data from differentsystems for user console 1225.

Each of the different controls may control individual devices/apparatus.Master network controller 1205 controls windows 1255. Lighting controlpanel 1210 controls lights 1235. BMS 1215 may control HVAC 1230.Security control system 1220 controls security sensors 1240, door locks1245, and cameras 1250. Data may be exchanged and/or shared between allof the different devices/apparatus and controllers that are part ofbuilding network 1200.

In some cases, the systems of BMS 1100 or building network 1200 may runaccording to daily, monthly, quarterly, or yearly schedules. Forexample, the lighting control system, the window control system, theHVAC, and the security system may operate on a 24 hour scheduleaccounting for when people are in the building during the work day. Atnight, the building may enter an energy savings mode, and during theday, the systems may operate in a manner that minimizes the energyconsumption of the building while providing for occupant comfort. Asanother example, the systems may shut down or enter an energy savingsmode over a holiday period.

The scheduling information may be combined with geographicalinformation. Geographical information may include the latitude andlongitude of the building. Geographical information also may includeinformation about the direction that each side of the building faces.Using such information, different rooms on different sides of thebuilding may be controlled in different manners. For example, for eastfacing rooms of the building in the winter, the window controller mayinstruct the windows to have no tint in the morning so that the roomwarms up due to sunlight shining in the room and the lighting controlpanel may instruct the lights to be dim because of the lighting from thesunlight. The west facing windows may be controllable by the occupantsof the room in the morning because the tint of the windows on the westside may have no impact on energy savings. However, the modes ofoperation of the east facing windows and the west facing windows mayswitch in the evening (e.g., when the sun is setting, the west facingwindows are not tinted to allow sunlight in for both heat and lighting).

Described below is an example of a building, for example, like building1101 in FIG. 15, including a building network or a BMS, tintable windowsfor the exterior windows of the building (i.e., windows separating theinterior of the building from the exterior of the building), and anumber of different sensors. Light from exterior windows of a buildinggenerally has an effect on the interior lighting in the building about20 feet or about 30 feet from the windows. That is, space in a buildingthat is more that about 20 feet or about 30 feet from an exterior windowreceives little light from the exterior window. Such spaces away fromexterior windows in a building are lit by lighting systems of thebuilding.

Further, the temperature within a building may be influenced by exteriorlight and/or the exterior temperature. For example, on a cold day andwith the building being heated by a heating system, rooms closer todoors and/or windows will lose heat faster than the interior regions ofthe building and be cooler compared to the interior regions.

For exterior sensors, the building may include exterior sensors on theroof of the building. Alternatively, the building may include anexterior sensor associated with each exterior window (e.g., as describedin relation to FIG. 5, room 500) or an exterior sensor on each side ofthe building. An exterior sensor on each side of the building couldtrack the irradiance on a side of the building as the sun changesposition throughout the day.

Regarding the methods described with respect to FIGS. 7, 8, 9, 12, 13,and 14, when a window controller is integrated into a building networkor a BMS, outputs from exterior sensors 510 may be input to a network ofBMS and provided as input to the local window controller 450. Forexample, in some embodiments, output signals from any two or moresensors are received. In some embodiments, only one output signal isreceived, and in some other embodiments, three, four, five, or moreoutputs are received. These output signals may be received over abuilding network or a BMS.

In some embodiments, the output signals received include a signalindicating energy or power consumption by a heating system, a coolingsystem, and/or lighting within the building. For example, the energy orpower consumption of the heating system, the cooling system, and/or thelighting of the building may be monitored to provide the signalindicating energy or power consumption. Devices may be interfaced withor attached to the circuits and/or wiring of the building to enable thismonitoring. Alternatively, the power systems in the building may beinstalled such that the power consumed by the heating system, a coolingsystem, and/or lighting for an individual room within the building or agroup of rooms within the building can be monitored.

Tint instructions can be provided to change to tint of the tintablewindow to the determined level of tint. For example, referring to FIG.15, this may include master network controller 1103 issuing commands toone or more intermediate network controllers 1105 a and 1105 b, which inturn issue commands to end controllers 1110 that control each window ofthe building. End controllers 1100 may apply voltage and/or current tothe window to drive the change in tint pursuant to the instructions.

In some embodiments, a building including electrochromic windows and aBMS may be enrolled in or participate in a demand response program runby the utility or utilities providing power to the building. The programmay be a program in which the energy consumption of the building isreduced when a peak load occurrence is expected. The utility may sendout a warning signal prior to an expected peak load occurrence. Forexample, the warning may be sent on the day before, the morning of, orabout one hour before the expected peak load occurrence. A peak loadoccurrence may be expected to occur on a hot summer day when coolingsystems/air conditioners are drawing a large amount of power from theutility, for example. The warning signal may be received by the BMS ofthe building or by window controllers configured to control theelectrochromic windows in the building. This warning signal can be anoverride mechanism that disengages the Modules A, B, and C as shown inFIG. 7. The BMS can then instruct the window controller(s) to transitionthe appropriate electrochromic device in the electrochromic windows 505to a dark tint level aid in reducing the power draw of the coolingsystems in the building at the time when the peak load is expected.

In some embodiments, tintable windows for the exterior windows of thebuilding (i.e., windows separating the interior of the building from theexterior of the building), may be grouped into zones, with tintablewindows in a zone being instructed in a similar manner. For example,groups of electrochromic windows on different floors of the building ordifferent sides of the building may be in different zones. For example,on the first floor of the building, all of the east facingelectrochromic windows may be in zone 1, all of the south facingelectrochromic windows may be in zone 2, all of the west facingelectrochromic windows may be in zone 3, and all of the north facingelectrochromic windows may be in zone 4. As another example, all of theelectrochromic windows on the first floor of the building may be in zone1, all of the electrochromic windows on the second floor may be in zone2, and all of the electrochromic windows on the third floor may be inzone 3. As yet another example, all of the east facing electrochromicwindows may be in zone 1, all of the south facing electrochromic windowsmay be in zone 2, all of the west facing electrochromic windows may bein zone 3, and all of the north facing electrochromic windows may be inzone 4. As yet another example, east facing electrochromic windows onone floor could be divided into different zones. Any number of tintablewindows on the same side and/or different sides and/or different floorsof the building may be assigned to a zone.

In some embodiments, electrochromic windows in a zone may be controlledby the same window controller. In some other embodiments, electrochromicwindows in a zone may be controlled by different window controllers, butthe window controllers may all receive the same output signals fromsensors and use the same function or lookup table to determine the levelof tint for the windows in a zone.

In some embodiments, electrochromic windows in a zone may be controlledby a window controller or controllers that receive an output signal froma transmissivity sensor. In some embodiments, the transmissivity sensormay be mounted proximate the windows in a zone. For example, thetransmissivity sensor may be mounted in or on a frame containing an IGU(e.g., mounted in or on a mullion, the horizontal sash of a frame)included in the zone. In some other embodiments, electrochromic windowsin a zone that includes the windows on a single side of the building maybe controlled by a window controller or controllers that receive anoutput signal from a transmissivity sensor.

In some embodiments, a sensor (e.g., photosensor) may provide an outputsignal to a window controller to control the electrochromic windows 505of a first zone (e.g., a master control zone). The window controller mayalso control the electrochromic windows 505 in a second zone (e.g., aslave control zone) in the same manner as the first zone. In some otherembodiments, another window controller may control the electrochromicwindows 505 in the second zone in the same manner as the first zone.

In some embodiments, a building manager, occupants of rooms in thesecond zone, or other person may manually instruct (using a tint orclear command or a command from a user console of a BMS, for example)the electrochromic windows in the second zone (i.e., the slave controlzone) to enter a tint level such as a colored state (level) or a clearstate. In some embodiments, when the tint level of the windows in thesecond zone is overridden with such a manual command, the electrochromicwindows in the first zone (i.e., the master control zone) remain undercontrol of the window controller receiving output from thetransmissivity sensor. The second zone may remain in a manual commandmode for a period of time and then revert back to be under control ofthe window controller receiving output from the transmissivity sensor.For example, the second zone may stay in a manual mode for one hourafter receiving an override command, and then may revert back to beunder control of the window controller receiving output from thetransmissivity sensor.

In some embodiments, a building manager, occupants of rooms in the firstzone, or other person may manually instruct (using a tint command or acommand from a user console of a BMS, for example) the windows in thefirst zone (i.e., the master control zone) to enter a tint level such asa colored state or a clear state. In some embodiments, when the tintlevel of the windows in the first zone is overridden with such a manualcommand, the electrochromic windows in the second zone (i.e., the slavecontrol zone) remain under control of the window controller receivingoutputs from the exterior sensor. The first zone may remain in a manualcommand mode for a period of time and then revert back to be undercontrol of window controller receiving output from the transmissivitysensor. For example, the first zone may stay in a manual mode for onehour after receiving an override command, and then may revert back to beunder control of the window controller receiving output from thetransmissivity sensor. In some other embodiments, the electrochromicwindows in the second zone may remain in the tint level that they are inwhen the manual override for the first zone is received. The first zonemay remain in a manual command mode for a period of time and then boththe first zone and the second zone may revert back to be under controlof the window controller receiving output from the transmissivitysensor.

Any of the methods described herein of control of a tintable window,regardless of whether the window controller is a standalone windowcontroller or is interfaced with a building network, may be used controlthe tint of a tintable window.

Wireless or Wired Communication

In some embodiments, window controllers described herein includecomponents for wired or wireless communication between the windowcontroller, sensors, and separate communication nodes. Wireless or wiredcommunications may be accomplished with a communication interface thatinterfaces directly with the window controller. Such interface could benative to the microprocessor or provided via additional circuitryenabling these functions.

A separate communication node for wireless communications can be, forexample, another wireless window controller, an end, intermediate, ormaster window controller, a remote control device, or a BMS. Wirelesscommunication is used in the window controller for at least one of thefollowing operations: programming and/or operating the electrochromicwindow 505, collecting data from the EC window 505 from the varioussensors and protocols described herein, and using the electrochromicwindow 505 as a relay point for wireless communication. Data collectedfrom electrochromic windows 505 also may include count data such asnumber of times an EC device has been activated, efficiency of the ECdevice over time, and the like. These wireless communication features isdescribed in more detail below.

In one embodiment, wireless communication is used to operate theassociated electrochromic windows 505, for example, via an infrared(IR), and/or radio frequency (RF) signal. In certain embodiments, thecontroller will include a wireless protocol chip, such as Bluetooth,EnOcean, WiFi, Zigbee, and the like. Window controllers may also havewireless communication via a network. Input to the window controller canbe manually input by an end user at a wall switch, either directly orvia wireless communication, or the input can be from a BMS of a buildingof which the electrochromic window is a component.

In one embodiment, when the window controller is part of a distributednetwork of controllers, wireless communication is used to transfer datato and from each of a plurality of electrochromic windows via thedistributed network of controllers, each having wireless communicationcomponents. For example, referring again to FIG. 15, master networkcontroller 1103, communicates wirelessly with each of intermediatenetwork controllers 1105 a and 1105 b, which in turn communicatewirelessly with end controllers 1110, each associated with anelectrochromic window. Master network controller 1103 may alsocommunicate wirelessly with the BMS 1100. In one embodiment, at leastone level of communication in the window controller is performedwirelessly.

In some embodiments, more than one mode of wireless communication isused in the window controller distributed network. For example, a masterwindow controller may communicate wirelessly to intermediate controllersvia WiFi or Zigbee, while the intermediate controllers communicate withend controllers via Bluetooth, Zigbee, EnOcean, or other protocol. Inanother example, window controllers have redundant wirelesscommunication systems for flexibility in end user choices for wirelesscommunication.

Wireless communication between, for example, master and/or intermediatewindow controllers and end window controllers offers the advantage ofobviating the installation of hard communication lines. This is alsotrue for wireless communication between window controllers and BMS. Inone aspect, wireless communication in these roles is useful for datatransfer to and from electrochromic windows for operating the window andproviding data to, for example, a BMS for optimizing the environment andenergy savings in a building. Window location data as well as feedbackfrom sensors are synergized for such optimization. For example, granularlevel (window-by-window) microclimate information is fed to a BMS inorder to optimize the building's various environments.

VI. Example of System for Controlling Functions of Tintable Windows

FIG. 17 is a block diagram of components of a system 1400 forcontrolling functions (e.g., transitioning to different tint levels) ofone or more tintable windows of a building (e.g., building 1101 shown inFIG. 15), according to embodiments. System 1400 may be one of thesystems managed by a BMS (e.g., BMS 1100 shown in FIG. 15) or mayoperate independently of a BMS.

System 1400 includes a master window controller 1402 that can sendcontrol signals to the tintable windows to control its functions. System1400 also includes a network 1410 in electronic communication withmaster window controller 1402. The predictive control logic, othercontrol logic and instructions for controlling functions of the tintablewindow(s), and/or sensor data may be communicated to the master windowcontroller 1402 through the network 1410. Network 1410 can be a wired orwireless network (e.g. cloud network). In one embodiment, network 1410may be in communication with a BMS to allow the BMS to send instructionsfor controlling the tintable window(s) through network 1410 to thetintable window(s) in a building.

System 1400 also includes EC devices 400 of the tintable windows (notshown) and wall switches 1490, which are both in electroniccommunication with master window controller 1402. In this illustratedexample, master window controller 1402 can send control signals to ECdevice(s) 400 to control the tint level of the tintable windows havingthe EC device(s) 400. Each wall switch 1490 is also in communicationwith EC device(s) 400 and master window controller 1402. An end user(e.g., occupant of a room having the tintable window) can use the wallswitch 1490 to control the tint level and other functions of thetintable window having the EC device(s) 400.

In FIG. 17, master window controller 1402 is depicted as a distributednetwork of window controllers including a master network controller1403, a plurality of intermediate network controllers 1405 incommunication with the master network controller 1403, and multiplepluralities of end or leaf window controllers 1410. Each plurality ofend or leaf window controllers 1410 is in communication with a singleintermediate network controller 1405. Although master window controller1402 is illustrated as a distributed network of window controllers,master window controller 1402 could also be a single window controllercontrolling the functions of a single tintable window in otherembodiments. The components of the system 1400 in FIG. 17 may be similarin some respects to components described with respect to FIG. 15. Forexample, master network controller 1403 may be similar to master networkcontroller 1103 and intermediate network controllers 1405 may be similarto intermediate network controllers 1105. Each of the window controllersin the distributed network of FIG. 17 may include a processor (e.g.,microprocessor) and a computer readable medium in electricalcommunication with the processor.

In FIG. 17, each leaf or end window controller 1410 is in communicationwith EC device(s) 400 of a single tintable window to control the tintlevel of that tintable window in the building. In the case of an IGU,the leaf or end window controller 1410 may be in communication with ECdevices 400 on multiple lites of the IGU control the tint level of theIGU. In other embodiments, each leaf or end window controller 1410 maybe in communication with a plurality of tintable windows. The leaf orend window controller 1410 may be integrated into the tintable window ormay be separate from the tintable window that it controls. Leaf and endwindow controllers 1410 in FIG. 17 may be similar to the end or leafcontrollers 1110 in FIG. 15 and/or may also be similar to windowcontroller 450 described with respect to FIG. 4.

Each wall switch 1490 can be operated by an end user (e.g., occupant ofthe room) to control the tint level and other functions of the tintablewindow in communication with the wall switch 1490. The end user canoperate the wall switch 1490 to communicate control signals to the ECdevices 400 in the associated tintable window. These signals from thewall switch 1490 may override signals from master window controller 1402in some cases. In other cases (e.g., high demand cases), control signalsfrom the master window controller 1402 may override the control signalsfrom wall switch 1490. Each wall switch 1490 is also in communicationwith the leaf or end window controller 1410 to send information aboutthe control signals (e.g. time, date, tint level requested, etc.) sentfrom wall switch 1490 back to master window controller 1402. In somecases, wall switches 1490 may be manually operated. In other cases, wallswitches 1490 may be wirelessly controlled by the end user using aremote device (e.g., cell phone, tablet, etc.) sending wirelesscommunications with the control signals, for example, using infrared(IR), and/or radio frequency (RF) signals. In some cases, wall switches1490 may include a wireless protocol chip, such as Bluetooth, EnOcean,WiFi, Zigbee, and the like. Although wall switches 1490 depicted in FIG.17 are located on the wall(s), other embodiments of system 1400 may haveswitches located elsewhere in the room.

VII. Another Example of Predictive Control Logic

FIG. 18 is a block diagram depicting predictive control logic for amethod of controlling the tint level of one or more tintable windows(e.g., electrochromic windows) in different zones of a building,according to embodiments. This logic makes predictive determinations ata time in the future that accounts for the transition time of the ECdevices 400 in the tintable windows. This predictive control logic canbe employed by components of system 1400 described with respect to FIG.17 or by components of systems of other disclosed embodiments. In theillustrated example, a portion of the predictive control logic isperformed by window controller 1410, another portion is performed bynetwork controller 1408, and the logic in Module 1 1406 is performed bya separate component from the window controller 1410 and networkcontroller 1408. Alternatively, Module 1 1406 may be separate logic thatmay or may not be loaded onto the window controller 1410.

In FIG. 18, the portions of the predictive control logic employed bywindow controller 1410 and Module 1 1406 are managed by BMS 1407. BMS1407 may be similar to BMS 1100 described with respect to FIG. 15. BMS1407 is in electronic communication with window controller 1410 througha BACnet Interface 1408. In other embodiments, other communicationsprotocol may be used. Although not shown in FIG. 18, Module 1 1406 isalso in communication with BMS 1407 through BACnet Interface 1408. Inother embodiments, the predictive control logic depicted in FIG. 18 mayoperate independently of a BMS.

Network controller 1408 receives sensor readings from one or moresensors (e.g., an outside light sensor) and may also convert the sensorreading into W/m². The network controller 1408 is in electroniccommunication with the window controller 1410 via either CANbus orCANOpen protocol. The network controller 1408 communicates the convertedsensor readings to the window controller 1410. Network controller 1408may be similar to either the intermediate network controller 1405 or themaster network controller 1403 of FIG. 17.

In FIG. 18, the portion of the predictive control logic employed bywindow controller 1410 includes a master scheduler 1502. The masterscheduler 1502 includes logic that allows a user (e.g., buildingadministrator) to prepare a schedule that can use different types ofcontrol programs at different times of day and/or dates. Each of thecontrol programs includes logic for determining a tint level based on ormore independent variables. One type of control program is simply a purestate. A pure state refers to particular level of tint (e.g.,transmissivity=40%) that is fixed during a certain time period,regardless of other conditions. For example, the building manager mayspecify that the windows are clear after 3 PM every day. As anotherexample, building manager may specify a pure state for the time periodbetween the hours of 8 PM to 6 AM every day. At other times of day, adifferent type of control program may be employed, for example, oneemploying a much greater level of sophistication. One type of controlprogram offering a high level of sophistication. For example, a highlysophisticated control program of this type includes predictive controllogic described in reference to FIG. 18 and may include theimplementation of one or more of the logic Modules A, B, and C of Module1 1406. As another example, another highly sophisticated control programof this type includes predictive control logic described in reference toFIG. 18 and may include the implementation of one or more of the logicModules A, B, and C of Module 1 1406 and Module D described later inthis Section VII. As another example, another highly sophisticatedcontrol program of this type is the predictive control logic describedin reference to FIG. 7 and includes full multi-module implementation oflogic Modules A, B, and C described in reference to FIGS. 8, 9, and 12.In this example, the predictive control logic uses sensor feedback inModule C and solar information in Modules A and B. Another example of ahighly sophisticated control program is the predictive control logicdescribed in reference to FIG. 7 with partial logic moduleimplementation of one or two of the logic Modules A, B, and C describedin reference to FIGS. 8, 9, and 12. Another type of control program is athreshold control program that relies on feedback from one or moresensors (e.g., photosensors) and adjusts the tint level accordinglywithout regard to solar position. One of the technical advantages ofusing master scheduler 1502 is that the user can select and schedule thecontrol program (method) being used to determine the tint level.

Master scheduler 1502 runs the control programs in the scheduleaccording to time in terms of the date and time of day based on a24-hour day. Master scheduler 1502 may determine the date in terms of acalendar date and/or the day of the week based on a 7-day week with fiveweekdays (Monday through Friday) and two weekend days (Saturday andSunday). Master scheduler 1502 may also determine whether certain daysare holidays. Master scheduler 1502 may automatically adjust the time ofday for daylight savings time based on the location of the tintablewindows, which is determined by site data 1506.

In one embodiment, master scheduler 1502 may use a separate holidayschedule. The user may have determined which control program(s) to useduring the holiday schedule. The user may determine which days will beincluded in the holiday schedule. Master scheduler 1502 may copy thebasic schedule set up by the user and allow the user to set up theirmodifications for the holidays in the holiday schedule.

When preparing the schedule employed by master scheduler 1502, the usermay select the zone or zones (Zone Selection) of the building where theselected program(s) will be employed. Each zone includes one or moretintable windows. In some cases, a zone may be an area associated with aspace type (e.g., offices having a desk at a particular position,conference rooms, etc.) or may be associated with multiple space types.For example, the user may select Zone 1 having offices to: 1) Mondaythrough Friday: heat up at 8 am in morning to 70 degrees and turn on airconditioning to at 3 pm in afternoon to keep temperature in offices to80 degrees, and then turn off all air conditioning, and heat at 5 pmduring weekdays, and 2) (Saturday and Sunday) turn off heat and airconditioning. As another example, the user may set Zone 2 having aconference room to run the predictive control logic of FIG. 18 includingfull-module implementation of Module 1 using all of the logic Module A,B, and C. In another example, the user may select a Zone 1 havingconference rooms to run Module 1 from 8 AM to 3 PM and a thresholdprogram or pure state after 3 PM. In other cases, a zone may be theentire building or may be one or more windows in a building.

When preparing the schedule with programs that may use sensor input, theuser may also be able to select the sensor or sensors used in theprograms. For example, the user may select a sensor located on the roofor a sensor located near or at the tintable window. As another example,the user may select an ID value of a particular sensor.

The portion of the predictive control logic employed by windowcontroller 1410 also includes a user interface 1504 in electroniccommunication with master scheduler 1502. User interface 1504 is also incommunication with site data 1506, zone/group data 1508, and sense logic1516. The user may input their schedule information to prepare theschedule (generate a new schedule or modify an existing schedule) usinguser interface 1504. User interface 1504 may include an input devicesuch as, for example, a keypad, touchpad, keyboard, etc. User interface1504 may also include a display to output information about the scheduleand provide selectable options for setting up the schedule. Userinterface 1504 is in electronic communication with a processor (e.g.,microprocessor), which is in electronic communication with a computerreadable medium (CRM). Both the processor and CRM are components of thewindow controller 1410. The logic in master scheduler 1502 and othercomponents of the predictive control logic may be stored on the computerreadable medium of window controller 1410.

The user may enter their site data 1506 and zone/group data 1508 usinguser interface 1504. Site data 1506 includes the latitude, longitude,and GMT Offset for the location of the building. Zone/group dataincludes the position, dimension (e.g., window width, window height,sill width, etc.), orientation (e.g., window tilt), external shading(e.g., overhang depth, overhang location above window, left/right fin toside dimension, left/right fin depth, etc.), datum glass SHGC, andoccupancy lookup table for the one or more tintable windows in each zoneof the building. In FIG. 18, site data 1506 and zone/group data 1508 isstatic information (i.e. information that is not changed by componentsof the predictive control logic). In other embodiments, this data may begenerated on the fly. Site data 1506 and zone/group data 1508 may bestored on a computer readable medium of the window controller 1410.

When preparing (or modifying) the schedule, the user selects the controlprogram that master scheduler 1502 will run at different time periods ineach of the zones of a building. In some cases, the user may be able toselect from multiple control programs. In one such case, the user mayprepare a schedule by selecting a control program from a list of allcontrol programs (e.g., menu) displayed on user interface 1405. In othercases, the user may have limited options available to them from a listof all control programs. For example, the user may have only paid forthe use of two control programs. In this example, the user would only beable to select one of the two control programs paid for by the user.

An example of a user interface 1405 is shown in FIG. 19. In thisillustrated example, the user interface 1405 is in the form of a tablefor entering schedule information used to generate or change a scheduleemployed by the master scheduler 1502. For example, the user can enterthe time period into the table by entering start and stop times. Theuser can also select a sensor used by a program. The user can also enterSite data 1506 and Zone/Group Data 1508. The user can also select anoccupancy lookup table to be used by selecting “Sun Penetration Lookup.”

Returning to FIG. 18, the portion of the predictive control logicemployed by window controller 1410 also includes time of day (lookahead) logic 1510. Time of day (look ahead) logic 1510 determines a timein the future used by predictive control logic to make its predictivedeterminations. This time in the future accounts for time needed totransition the tint level of the EC devices 400 in the tintable windows.By using a time that accounts for transition time, the predictivecontrol logic can predict a tint level appropriate for the future timeat which time the EC devices 400 will have had the time to transition tothe tint level after receiving the control signal. Time of day portion1510 may estimate the transition time of EC device(s) in arepresentative window based on information about the representativewindow (e.g., window dimension, etc.) from the Zone/Group Data. Time ofday logic 1510 may then determine the future time based on thetransition time and the current time. For example, the future time maybe equal to or greater than the current time added to the transitiontime.

The Zone/Group Data includes information about the representative windowof each zone. In one case, the representative window may be one of thewindows in the zone. In another case, the representative window may be awindow having average properties (e.g., average dimensions) based onaveraging all the properties from all the windows in that zone.

The predictive control logic employed by window controller 1410 alsoincludes a solar position calculator 1512. Solar position calculator1512 includes logic that determines the position of the sun, sun azimuthand sun altitude, at an instance in time. In FIG. 18, solar positioncalculator 1512 makes its determinations based on a future instance intime received from time of day logic 1510. Solar position calculator1512 is in communication with time of day portion 1510 and site data1506 to receive the future time, latitude and longitude coordinates ofthe building, and other information that may be needed to make itscalculation(s), such as the solar position calculation. Solar positioncalculator 1512 may also perform one or more determinations based on thecalculated solar position. In one embodiment, solar position calculator1512 may calculate clear sky irradiance or make other determinationsfrom Modules A, B, and C of Module 1 1406.

The control logic employed by window controller 1410 also includesschedule logic 1518, which is in communication with the sense logic1516, the user interface 1405, the solar position calculator 1512, andModule 1 1406. The schedule logic 1518 includes logic that determineswhether to use the tint level passing through the intelligence logic1520 from Module 1 1406 or use another tint level based on otherconsiderations. For example, as sunrise and sunset times changethroughout the year, the user may not want to reprogram the schedule toaccount for these changes. The schedule logic 1518 may use the sunriseand sunset times from the solar position calculator 1512 to set anappropriate tint level before sunrise and after sunset without requiringthe user to reprogram the schedule for these changing times. Forexample, the schedule logic 1508 may determine that according to thesunrise time received from the solar position calculator 1512 the sunhas not risen and that a pre-sunrise tint level should be used insteadof the tint level passed from Module 1 1406. The tint level determinedby the schedule logic 1518 is passed to sense logic 1516.

Sense logic 1516 is in communication with override logic 1514, schedulelogic 1518, and user interface 1405. Sense logic 1516 includes logicthat determines whether to use the tint level passed from schedule logic1516 or use another tint level based on the sensor data received throughthe BACnet interface 1408 from one or more sensors. Using the example inthe paragraph above, if schedule logic 1518 determines that it the sunhas not risen and passed a pre-sunrise tint level and the sensor datashows that the sun has actually risen, then sense logic 1516 would usethe tint level passed from Module 1 1406 through schedule logic 1518.The tint level determined by sense logic 1516 is passed to overridelogic 1514.

BMS 1407 and network controller 1408 are also in electroniccommunication with a demand response (e.g., utility company) to receivesignals communicating the need for a high demand (or peak load)override. In response to receiving these signals from the demandresponse, BMS 1407 and/or network controller 1408 may send instructionsthrough BACnet Interface 1408 to override logic 1514 that will processthe override information from the demand response. Override logic 1514is in communication with BMS 1407 and network controller 1408 throughthe BACnet Interface 1408, and also in communication with sense logic1516.

Override logic 1514 allows for certain types of overrides to disengagepredictive control logic and use an override tint level based on anotherconsideration. Some examples of types of overrides that may disengagepredictive control logic include a high demand (or peak load) override,manual override, vacant room override, etc. A high demand (or peak load)override defines a tint level from the demand response. For a manualoverride, an end user may enter the override value at a wall switch 1490(shown in FIG. 17) either manually or through a remote device. A vacantroom override defines an override value based on a vacant room (i.e. nooccupant in the room). In this case, the sense logic 1516 may receivesensor data from a sensor (e.g., motion sensor) indicating that the roomis vacant and sense logic 1516 may determine an override value and relaythe override value to override logic 1514. The override logic 1514 canreceive an override value and determine whether to use the overridevalue or use another value, such as another override value received froma source having higher priority (i.e., demand response). In some cases,the override logic 1514 may operate by steps similar to the overridesteps 630, 640, and 650 described with respect to FIG. 7.

The control logic employed by window controller 1410 also includesintelligence logic 1520 that can shut off one or more of Modules A 1550,B 1558 and C 1560. In one case, the intelligence logic 1520 may be usedto shut off one or more Modules where the user has not paid for thoseModules. Intelligence logic 1520 may prevent the use of certain moresophisticated features such as the penetration calculation made inModule A. In such cases, a basic logic is used that “short-circuits” thesolar calculator information and uses it to calculate tint levels,possibly with the assistance of one or more sensors. This tint levelfrom the basic logic is communicated to schedule logic 1518.

Intelligence logic 1520 can shut off one or more of the Modules (ModuleA 1550, Module B 1558 and Module C 1560) by diverting certaincommunications between the window controller 1410 and Module 1 1406. Forexample, the communication between the solar position calculator 1512and Module A 1550 goes through intelligence logic 1520 and can bediverted to schedule logic 1518 by intelligence logic 1520 to shut offModule A 1550, Module B 1558 and Module C 1560. As another example, thecommunication of tint level from Module A at 1552 to the Clear SkyIrradiance calculations at 1554 goes through intelligence logic 1520 andcan be diverted instead to schedule logic 1518 to shut off Module B 1558and Module C 1560. In yet another example, the communication of tintlevel from Module B at 1558 to Module C 1560 goes through intelligencelogic 1520 and can be diverted to schedule logic 1518 to shut off ModuleC 1560.

Module 1 1406 includes logic that determines and returns a tint level tothe schedule logic 1518 of window controller 1410. The logic predicts atint level that would be appropriate for the future time provided by thetime of day portion 1510. The tint level is determined for arepresentative tintable window associated with each of the zones in theschedule.

In FIG. 18, Module 1 1406 includes Module A 1550, Module B 1558 andModule C 1560, which may have some steps that are similar in somerespects to the steps performed in Modules A, B, and C as described withrespect to FIGS. 8, 9, 12 and 13. In another embodiment, Module 1 1406may be comprised of Modules A, B, and C as described with respect toFIGS. 8, 9, 12 and 13. In yet another embodiment, Module 1 1406 may becomprised of Modules A, B, and C described with respect to FIG. 14.

In FIG. 18, Module A 1550 determines the penetration depth through therepresentative tintable window. The penetration depth predicted byModule A 1550 is at the future time. Module A 1550 calculates thepenetration depth based on the determined position of the sun (i.e. sunazimuth and sun altitude) received from the solar position calculator1512 and based on the position of the representative tintable window,acceptance angle, dimensions of the window, orientation of the window(i.e. direction facing), and the details of any exterior shadingretrieved from the zone/group data 1508.

Module A 1550 then determines the tint level that will provide occupantcomfort for the calculated penetration depth. Module A 1550 uses theoccupancy lookup table retrieved from the zone/group data 1508 todetermine the desired tint level for the space type associated with therepresentative tintable window, for the calculated penetration depth,and for the acceptance angle of the window. Module A 1550 outputs a tintlevel at step 1552.

The maximum clear sky irradiance incident the representative tintablewindow is predicted for all times in the logic 1554. The clear skyirradiance at the future time is also predicted based on the latitudeand longitude coordinates of the building and the representative windoworientation (i.e. direction the window is facing) from the site data1506 and the zone/group data 1508. These clear sky irradiancecalculations can be performed by the sun position calculator 1512 inother embodiments.

Module B 1556 then calculates new tint levels by incrementallyincreasing the tint level. At each of these incremental steps, theInside Irradiance in the room based on the new tint level is determinedusing the equation: Inside Irradiance=Tint level SHGC×Clear SkyIrradiance. Module B selects the tint level where Inside Irradiance isless than or equal to Datum Inside Irradiance (Datum SHGC×Max. Clear skyIrradiance) and the tint level is not lighter than Tint Level from A.Module B 1556 outputs the selected tint level from B. From the Tintlevel from B, logic 1558 calculates the outside irradiance and thecalculated skylight irradiance.

Module C 1560 makes a determination of whether a sensor reading ofirradiance is less than the clear sky irradiance. If the determinationresult is YES, then the tint level being calculated is madeincrementally lighter (clearer) until the value matches or is less thana tint level calculated as Sensor Reading×Tint Level SHGC, but not toexceed datum inside Irradiance from B. If the determination result isNO, then the tint level being calculated is made darker in incrementalsteps as done in Module B 1556. Module C outputs the tint level. Logic1562 determines that the tint level from Module C is the final tintlevel and returns this final tint level (Tint level from Module C) tothe schedule logic 1518 of the window controller 1410.

In one aspect, Module 1 1406 may also include a fourth Module D that canpredict the effects of the surrounding environment on the intensity anddirection of sunlight through the tintable windows in the zone. Forexample, a neighboring building or other structure may shade thebuilding and block some light from passing through the windows. Asanother example, reflective surfaces (e.g., surfaces having snow, water,etc.) from a neighboring building or other surfaces in the environmentsurrounding the building may reflect light into the tintable windows.This reflected light can increase the intensity of light into thetintable windows and cause glare in the occupant space. Depending on thevalues of the intensity and direction of sunlight predicted by Module D,Module D may modify the tint level determined from Modules A, B, and Cor may modify certain determinations from Modules A, B, and C such as,for example, the penetration depth calculation or the acceptance angleof the representative window in the Zone/Group data.

In some cases, a site study may be conducted to determine theenvironment surrounding the building and/or one or more sensors may beused to determine the effects of the surrounding environment.Information from the site study may be static information based onpredicting the reflectance and shading (surrounding) effects for a timeperiod (e.g., a year), or may be dynamic information that can be updatedon a periodic basis or other timed basis. In one case, Module D may usethe site study to modify the standard acceptance angle and associated θ₁and θ₂ (shown in FIG. 20) of the representative window of each zoneretrieved from the Zone/group data. Module D may communicate thismodified information regarding the representative windows other modulesof the predictive control logic. The one or more sensors employed byModule D to determine the effects of the surrounding environment may bethe same sensors used by other modules (e.g., by Module C) or may bedifferent sensors. These sensors may be specifically designed todetermine the effects of the surrounding environment for Module D.

To operate the predictive control logic shown in FIG. 18, the user firstprepares a schedule with details of the times and dates, zones, sensors,and programs used. Alternatively, a default schedule may be provided.Once the schedule is in place (stored), at certain time intervals (every1 minute, 5 minutes, 10 minutes, etc.) the time of day portion 1510determines a future time of day based on the current time and thetransition time of the EC device(s) 400 in the representative window oreach zone in the schedule. Using the zone/group data 1508 and site data1506, the solar position calculator 1512 determines the solar positionat the future (look ahead) time for each representative window of eachzone in the schedule. Based on the schedule prepared by the user, theintelligence logic 1520 is used to determine which program to employ foreach zone in the schedule. For each zone, the scheduled program isemployed and predicts an appropriate tint level for that future time. Ifthere is an override in place, an override value will be used. If thereis no override in place, then the tint level determined by the programwill be used. For each zone, the window controller 1410 will sendcontrol signals with the zone-specific tint level determined by thescheduled program to the associated EC device(s) 400 to transition thetint level of the tintable window(s) in that zone by the future time.

VIII. Example of Occupancy Lookup Table

FIG. 20 is an illustration including an example of an occupancy lookuptable. The tint level in the table is in terms of T_(vis) (visibletransmission). The table includes different tint levels (T_(vis) values)for different combinations of calculated penetration depth values (2feet, 4 feet, 8 feet, and 15 feet) for a particular space type and whenthe sun angle θ_(sun) is between the acceptance angle of the windowbetween θ₁=30 degrees and θ₂=120 degrees. The table is based on fourtint levels including 4% (lightest), 20%, 40%, and 63%. FIG. 20 alsoshows a diagram of a desk near a window and the acceptance angle of thewindow to sunlight having an angle θ_(sun) between the angle of θ₁ andθ₂. This diagram shows the relationship between the sun angle θ_(sun)and the location of the desk. When the angle of the sun θ_(sun) isbetween the angle of acceptance between θ₁ and θ₂, then the sunlightcould strike the surface of the desk. If the sun angle θ_(sun) isbetween the acceptance angle between θ₁ and θ₂ (If θ₁<θ_(sun)<θ₂) andthe penetration depth meets the criteria to tint the window, then thattint level determined by the occupancy lookup table is sent to thewindow controller, which sends control signals to the EC devices in thewindow to transition the window to the determined tint level. These twoangles θ₁ and θ₂ can be calculated or measured for each window, andstored in the zone/group data 1508 with the other window parameters forthat zone.

FIGS. 21A, 21B, and 21C are plan views of a portion of a building 2100,according to embodiments. Building 2100 may be similar in some respectsto the building 1101 in FIG. 15 and the rooms in building 2100 may besimilar in some respects to the room 500 described in FIGS. 5, 6A, 6B,and 6C. The portion of building 2100 includes three different spacetypes including: a desk in an office, a group of cubicles, and aconference room in the building 2100. FIGS. 21A, 21B, and 21C show thesun at different angles θ_(sun). These figures also illustrate thedifferent acceptance angles of the different types of windows inbuilding 2100. For example, the conference room with the largest windowwill have the largest acceptance angle allowing the most light into theroom. In this example, the T_(vis) values in an associated occupancylookup table may be relatively low (low transmissivity) for theconference room. If however, a similar window having the same acceptanceangle was instead in a solarium, then the T_(vis) values in anassociated occupancy lookup table may be higher values (highertransmissivity) to allow for more sunlight to enter the room.

IX. Subsystems

FIG. 22 is a block diagram of subsystems that may be present in windowcontrollers used to control the tint level or more tintable windows,according to embodiments. For example, window controllers depicted inFIG. 17 may have a processor (e.g., microprocessor) and a computerreadable medium in electronic communication with the processor.

The various components previously described in the Figures may operateusing one or more of the subsystems to facilitate the functionsdescribed herein. Any of the components in the Figures may use anysuitable number of subsystems to facilitate the functions describedherein. Examples of such subsystems and/or components are shown in aFIG. 22. The subsystems shown in FIG. 22 are interconnected via a systembus 2625. Additional subsystems such as a printer 2630, keyboard 2632,fixed disk 2634 (or other memory comprising computer readable media),display 2430, which is coupled to display adapter 2638, and others areshown. Peripherals and input/output (I/O) devices, which couple to I/Ocontroller 2640, can be connected to the computer system by any numberof means known in the art, such as serial port 2642. For example, serialport 2642 or external interface 2644 can be used to connect the computerapparatus to a wide area network such as the Internet, a mouse inputdevice, or a scanner. The interconnection via system bus allows theprocessor 2410 to communicate with each subsystem and to control theexecution of instructions from system memory 2646 or the fixed disk2634, as well as the exchange of information between subsystems. Thesystem memory 2646 and/or the fixed disk 2634 may embody a computerreadable medium. Any of these elements may be present in the previouslydescribed features.

In some embodiments, an output device such as the printer 2630 ordisplay 2430 of one or more systems can output various forms of data.For example, the system 1400 may output schedule information on adisplay to a user.

Modifications, additions, or omissions may be made to any of theabove-described predictive control logic, other control logic and theirassociated control methods (e.g., logic described with respect to FIG.18, logic described with respect to FIGS. 7, 8, 9, 12, and 13, and logicdescribed with respect to FIG. 14) without departing from the scope ofthe disclosure. Any of the logic described above may include more,fewer, or other logic components without departing from the scope of thedisclosure. Additionally, the steps of the described logic may beperformed in any suitable order without departing from the scope of thedisclosure.

Also, modifications, additions, or omissions may be made to theabove-described systems (e.g., system described with respect to FIG. 17)or components of a system without departing from the scope of thedisclosure. The components of the may be integrated or separatedaccording to particular needs. For example, the master networkcontroller 1403 and intermediate network controller 1405 may beintegrated into a single window controller. Moreover, the operations ofthe systems can be performed by more, fewer, or other components.Additionally, operations of the systems may be performed using anysuitable logic comprising software, hardware, other logic, or anysuitable combination of the preceding.

It should be understood that the present invention as described abovecan be implemented in the form of control logic using computer softwarein a modular or integrated manner. Based on the disclosure and teachingsprovided herein, a person of ordinary skill in the art will know andappreciate other ways and/or methods to implement the present inventionusing hardware and a combination of hardware and software.

Any of the software components or functions described in thisapplication, may be implemented as software code to be executed by aprocessor using any suitable computer language such as, for example,Java, C++ or Perl using, for example, conventional or object-orientedtechniques. The software code may be stored as a series of instructions,or commands on a computer readable medium, such as a random accessmemory (RAM), a read only memory (ROM), a magnetic medium such as ahard-drive or a floppy disk, or an optical medium such as a CD-ROM. Anysuch computer readable medium may reside on or within a singlecomputational apparatus, and may be present on or within differentcomputational apparatuses within a system or network.

Although the foregoing disclosed embodiments have been described in somedetail to facilitate understanding, the described embodiments are to beconsidered illustrative and not limiting. It will be apparent to one ofordinary skill in the art that certain changes and modifications can bepracticed within the scope of the appended claims.

One or more features from any embodiment may be combined with one ormore features of any other embodiment without departing from the scopeof the disclosure. Further, modifications, additions, or omissions maybe made to any embodiment without departing from the scope of thedisclosure. The components of any embodiment may be integrated orseparated according to particular needs without departing from the scopeof the disclosure.

What is claimed is:
 1. A method of controlling tint of a tintable windowto account for occupant comfort in a room of a building, wherein thetintable window is located between the interior and exterior of thebuilding, the method comprising: (a) predicting a tint level for thetintable window at a future time based on a penetration depth of directsunlight through the tintable window into the room at the future timeand space type in the room; and (b) providing instructions over anetwork to transition tint of the tintable window to the tint leveldetermined in (a).
 2. The method of claim 1, further comprisingpredicting clear sky irradiance through the tintable window at thefuture time, and using the predicted clear sky irradiance together withthe determination in (a) to modify the tint level determined in (a). 3.The method of claim 2, further comprising receiving a signal from asensor configured to detect actual irradiance at the tintable window,and using the detected irradiance together with the determination in (a)to further modify the tint level.
 4. The method of claim 1, furthercomprising calculating the penetration depth in (a) based on sunposition at the future time and window configuration.
 5. The method ofclaim 4, wherein the future time is at least a preset interval after thecurrent time, wherein the preset interval is an estimated duration oftransitioning the tint of the tintable window.
 6. The method of claim 1,wherein the window configuration comprises values of one or morevariables selected from the group consisting of position of the window,dimensions of the window, orientation of the window, and dimensions ofexterior shading.
 7. The method of claim 1, wherein the tint level in(a) is determined using a lookup table in which tint levels arespecified for combinations of penetration depth and space type.
 8. Themethod of claim 1, further comprising calculating the sun position in(a) based on longitude and latitude of the building, and time of yearand a future time of day.
 9. The method of claim 1, wherein the tintlevel determined in (a) is a minimum tint level.
 10. The method of claim5, wherein the tint level determined in (a) reduces energy consumptionby a heating system, a cooling system, and/or lighting in the buildingwhile providing occupant comfort.
 11. The method of claim 1, furthercomprising using an override value to modify the tint level determinedin (a) after an override mechanism is received.
 12. The method of claim1, further comprising providing instructions wherein the instructionsare provided by a master controller.
 13. A controller for controllingtint of a tintable window to account for occupant comfort in a room of abuilding, wherein the tintable window is located between the interiorand exterior of the building, the controller comprising: a processorconfigured to determine a tint level for the tintable window based on apenetration depth of direct sunlight through the tintable window into aroom and space type in the room; and a power width modulator incommunication with the processor and with the tintable window over anetwork, the power width modulator configured to receiving the tintlevel from the processor and send a signal with tint instructions overthe network to transition the tint of the tintable window to thedetermined tint level.
 14. The controller of claim 13, wherein theprocessor is further configured to predict clear sky irradiance throughthe tintable window, and use the predicted clear sky irradiance togetherwith the determined tint level to modify the determined tint level. 15.The controller of claim 14, wherein the processor is in communicationwith a sensor configured to detect actual irradiance at the tintablewindow, and wherein the processor is further configured to receive asignal with detected irradiance from the sensor and use the detectedirradiance together with the modified tint level to further modify thetint level.
 16. A master controller for controlling tint of a tintablewindow to account for occupant comfort in a building, wherein thetintable window is located between the interior and exterior of thebuilding, the master controller comprising: a computer readable mediumhaving a configuration file with an space type associated with thetintable window; and a processor in communication with the computerreadable medium and in communication with a local window controller forthe tintable window, wherein the processor is configured to: receive thespace type from the computer readable medium, determine a tint level forthe tintable window based on a penetration depth of direct sunlightthrough the tintable window into a room and the space type, and sendtint instructions over a network to the local window controller totransition tint of the tintable window to the determined tint level. 17.A method of controlling tint of one or more tintable windows in a zoneof a building to account for occupant comfort, the method comprising:calculating a future time based on a current time and based on apredicted transition time of a representative window of the zone;predicting a solar position at the future time; determining a programdesignated by a user in a schedule, the program including logic fordetermining a tint level based on one or more independent variables;employing the determined program to determining the tint level based onthe predicted solar position at the future time and occupant comfort;and communicating instructions to the one or more tintable windows totransition tint to the determined tint level.
 18. The method of claim17, wherein the tintable windows are electrochromic windows and theinstructions are communicated to one or more electrochromic devices ofeach of the electrochromic windows.
 19. The method of claim 17, furthercomprising using intelligence logic to determine whether to use one ormore logic modules in the program to determine the tint level.
 20. Themethod of claim 19, further comprising if the intelligence logicdetermines to use a first logic module, determining the tint level basedon a penetration depth of direct sunlight through the representativewindow and based on space type.
 21. The method of claim 20, furthercomprising calculating the penetration depth based on the predictedsolar position and window configuration.
 22. The method of claim 20,further comprising modifying the calculated penetration depth based onsurrounding environment of the building.
 23. The method of claim 19,wherein the tint level is determined using a lookup table in which tintlevels are specified for combinations of penetration depth, space type,and acceptance angle.
 24. The method of claim 23, further comprisingmodifying the acceptance angle of the representative window based onsurrounding environment of the building.
 25. The method of claim 17,further comprising predicting clear sky irradiance through therepresentative window at the future time.
 26. The method of claim 19, ifthe intelligence logic determines to use a second logic module, furthercomprising: predicting clear sky irradiance through the representativewindow at the future time; and using the predicted clear sky irradiancealong with the predicted solar position to determine the tint level. 27.The method of claim 19, if the intelligence logic determines to use athird logic module, further comprising using actual irradiance detectedby a sensor to determine the tint level.
 28. The method of claim 19, ifthe intelligence logic determines to use both a first logic module and asecond logic module, further comprising: determining the tint levelbased on a penetration depth of direct sunlight through therepresentative window and based on space type; predicting clear skyirradiance through the representative window at the future time; andmodifying the tint level based on the predicted clear sky irradiancealong with the predicted solar position if darker.
 29. The method ofclaim 28, if the intelligence logic determines to also use a third logicmodule, further comprising using actual irradiance detected by a sensorto modify the tint level if darker.
 30. The method of claim 17, furthercomprising using override logic to determine whether to use an overridevalue to modify the determined tint level.
 31. The method of claim 17,wherein the schedule was prepared by a user.
 32. The method of claim 17,wherein the future time is calculated by adding the predicted transitiontime of the representative window to the current time.
 33. The method ofclaim 17, further comprising estimating the predicted transition time ofthe representative window.
 34. The method of claim 17, furthercomprising predicting the solar position at the predicted future timebased on longitude and latitude of the building.
 35. A window controllerfor controlling tint of one or more tintable windows in a zone of abuilding to account for occupant comfort, the window controllercomprising: a computer readable medium having predictive control logic,and site data and zone/group data associated with the zone; and aprocessor in communication with the computer readable medium and incommunication with the tintable window, wherein the processor isconfigured to: calculate a future time based on a current time and apredicted transition time of a representative window of the zone;predict a solar position at the future time; determine a programdesignated by a user in a schedule the program including logic fordetermining a tint level based on one or more independent variables;employ the determined program to determine a tint level using thepredicted solar position at the future time and based on occupantcomfort; and communicate instructions to the one or more tintablewindows in the zone to transition tint to the determined tint level. 36.The window controller of claim 35, wherein the tintable windows areelectrochromic windows and the instructions are communicated to one ormore electrochromic devices of each of the electrochromic windows.